Series-parallel connection type heat dissipation assembly heat balance calculation method

Abstract

The invention discloses a series-parallel connection type heat dissipation assembly heat balance calculation method, and the structure of a heat dissipation assembly comprises an oil radiator, a water radiator and an intercooler. A water radiator is arranged at the bottom of the oil radiator; an intercooler is arranged at the other end of the water radiator; according to the method, the cooling air resistance of the heat dissipation assembly is perfectly matched with the cooling air flow provided by the fan, convenience is provided for design and calculation, and the system heat balance parameter calculation precision is improved.

Description

Technical Field

[0001] The invention belongs to the field of heat balance calculation of a heat dissipation assembly, and in particular relates to a heat balance calculation method for a series-parallel type heat dissipation assembly. Background Art

[0002] Good heat dissipation of the vehicle power system is a necessary condition to ensure the normal operation of the vehicle. The heat dissipation demand of the power system mainly comes from the engine's intake air, water and system oil. Intercooler, water radiator and oil radiator are collectively referred to as the power system heat dissipation assembly. The engine intake cooling relies on the intercooler. The temperature and pressure of the outside air increase after supercharging. It is cooled by the intercooler before entering the engine to avoid the engine intake temperature being too high and affecting normal operation. A large amount of heat is generated during the operation of the engine. In order to keep the engine within the normal operating temperature range, water is generally used for liquid cooling. Therefore, a water radiator is used to cool the high-temperature water that has absorbed the heat of the engine. During the operation of the power system, the oil needs to be cooled and lubricated. If it is not cooled in time, the cooling and lubrication performance will be reduced, and the power performance of the vehicle will be reduced. Therefore, an oil radiator is used to cool the high-temperature oil.

[0003] The arrangement of the radiator will directly affect the heat dissipation performance and flow resistance of the heat dissipation assembly. Although the traditional three-series arrangement is simple in design, it brings huge cooling wind resistance to the heat dissipation assembly and is difficult to match with a suitable fan. The series-parallel arrangement, that is, the water radiator and the oil radiator are connected in series, and then connected in parallel with the air-to-air intercooler, makes the heat dissipation assembly more compact and reduces the cooling wind resistance. However, the series-parallel arrangement of the power system heat dissipation assembly faces the difficulty of matching resistance and flow calculation. The shortcomings of the existing thermal balance calculation technology make this type of calculation difficult and there are large errors. Specifically, first: the accurate distribution calculation of the cooling air flow of the intercooler, oil radiator, and water radiator cannot be achieved, resulting in large errors in the calculation of the air flow of each heat dissipation module. Second: the cooling air flow, flow resistance and fan characteristics of the heat dissipation assembly cannot be accurately matched, resulting in large errors in the calculation of the cooling air flow. Third: the influence of physical parameters, heat exchange temperature difference correction and fin efficiency changes on the calculation cannot be fully considered, resulting in large errors in the thermal balance calculation.

[0004] Therefore, the present invention proposes a series-parallel type heat dissipation assembly structure and a thermal balance calculation method, so that the cooling wind resistance of the heat dissipation assembly is perfectly matched with the cooling air flow provided by the fan, which provides convenience for design calculations and improves the calculation accuracy of the system thermal balance parameters.

[0005] The disadvantages of the existing technology are: 1) It fails to realize the heat balance calculation of the series-parallel mixed arrangement; 2) It fails to realize the heat balance calculation matching with the fan; 3) The calculation error is large, and the influence of physical parameters, heat exchange temperature difference correction and fin efficiency change on the calculation is not fully considered. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method for calculating the thermal balance of a series-parallel type heat dissipation assembly structure.

[0007] The specific technical solutions are as follows:

[0008] The series-parallel type heat dissipation assembly structure includes an oil radiator, a water radiator and an intercooler; the water radiator is arranged at the bottom of the oil radiator, and the intercooler is arranged at the other end of the water radiator.

[0009] Preferably, a method for calculating the thermal balance of a series-parallel type heat dissipation assembly comprises the following steps:

[0010] Step S1: input the core size, fin type, and fin size and structure parameters of each radiator in the heat dissipation assembly, where the subscripts c and h represent the low temperature side and the high temperature side of the radiator, respectively;

[0011] Step S2: Input the parameters of the hot and cold fluids flowing through each radiator: Oil flow rate m on the oil cooling side o , Water flow rate on water cooling side m w , Intercooler hot side intake volume m q , Oil inlet temperature T on the oil cooling side 11 ', water inlet temperature T on the water cooling side 21 '、Intercooler hot side inlet temperature T 31 '、Intercooler hot side outlet temperature T 31 ″、Inlet temperature of cooling air T a ;

[0012] Step S3: Assume that the cooling air volume m passing through the oil radiator and the water radiator 12 , Assume that the heat dissipation of the oil radiator is Q 1j , Assume that the heat dissipation of the water radiator is Q 2j , calculate the oil outlet temperature T on the oil cooling side 11 ″、Oil radiator cold side outlet temperature T 12 ″,

[0013]

[0014]

[0015] Among them, c o 、c 12 are the specific heat capacities of the engine oil and the cooling air on the cooling side of the oil radiator;

[0016] Step S4: Water outlet temperature T at the water cooling side 21 ″、Inlet temperature of cooling air on the cooling side of the water radiator T 22 '、Inlet temperature of cooling air on the cooling side of the water radiator T 22″:

[0017]

[0018] T 22 ′=T 12 ″

[0019]

[0020] Among them, c w 、c 22 are the specific heat capacities of water and cooling air respectively;

[0021] Step S5: Calculate the qualitative temperature of each working fluid based on the inlet and outlet temperatures of the oil radiator and the water radiator on the cold side and the hot side. The qualitative temperature is used to determine the physical parameters of each working fluid. The qualitative temperature of the oil on the oil radiator side is T 11 , Cooling air qualitative temperature T on the cooling side of the oil radiator 12 , water qualitative temperature T on the water cooling side 21 , Qualitative temperature of cooling air on the cooling side of water radiator T 22 :

[0022]

[0023]

[0024]

[0025]

[0026] Step S6: Calculate the P of the oil radiator according to the inlet and outlet temperatures of the oil radiator. 1 , R 1 Value, check the PR diagram to get the temperature difference correction coefficient n 1 ; Calculate the P of the water radiator according to the inlet and outlet temperatures of the water radiator 2 , R 2 Value, check the PR diagram to get the temperature difference correction coefficient n 2 :

[0027]

[0028]

[0029]

[0030]

[0031] Where, T' 21 Indicates the inlet temperature of the water cooling side; T' 12 Indicates the inlet temperature of the oil radiator on the cold side; T” 12 Indicates the outlet temperature of the oil radiator on the cold side; T”21 Indicates the outlet temperature of the water cooling side; T” 11 Indicates the outlet temperature of the oil heat dissipation side; T' 11 Indicates the inlet temperature of the oil heat dissipation side;

[0032] Step S7: Based on the temperature difference correction coefficient n 1 and n 2 , calculate the temperature difference ΔT on the cold and hot sides of the oil and water radiators respectively 1 , ΔT 2 , calculated using the average logarithmic temperature difference formula:

[0033]

[0034]

[0035] Step S8: According to the qualitative temperature of each working medium on the cold and hot sides of the oil radiator and the water radiator, determine the physical parameters of each working medium, and calculate the working medium flow rate u on the oil heat dissipation side and the cold side respectively. 11 、u 12 , calculate the working fluid flow rate u on the water cooling side and the cold side respectively 21 、u 22 :

[0036]

[0037]

[0038]

[0039]

[0040] Among them, ρ o , 12 , w and ρ 22 They are the density of the oil on the oil heat dissipation side, the density of the cooling air on the oil heat dissipation side, the density of the water on the water heat dissipation side, and the density of the cooling air on the water heat dissipation side;

[0041] Step S9: According to the qualitative temperature of each working fluid on the cold and hot sides of the oil radiator and the water radiator, determine the physical parameters of each working fluid, and calculate the working fluid flow Reynolds number Re on the oil heat dissipation side and the cold side respectively in combination with the obtained working fluid flow rate 11 、Re 12 , calculate the Reynolds number Re of the working fluid flow on the water cooling side and the cold side respectively 21 、Re 22 :

[0042]

[0043]

[0044]

[0045]

[0046] Among them, D h11 , D h12 , D h21 and D h22 are the hydraulic diameter of the fin on the oil heat dissipation side, the hydraulic diameter of the fin on the oil heat dissipation cooling side, the hydraulic diameter of the fin on the water heat dissipation side, and the hydraulic diameter of the fin on the water heat dissipation cooling side; μ 11 , μ 12 , μ 21 and μ 22 They are the dynamic viscosity of the oil on the oil heat dissipation side, the dynamic viscosity of the cooling air on the oil heat dissipation side, the dynamic viscosity of the water on the water heat dissipation side, and the dynamic viscosity of the cooling air on the water heat dissipation side;

[0047] Step S10: Calculate the j factor j of the hot side and the cold side respectively according to the structural dimension parameters of each fin on the cold side and the hot side of the oil radiator and the calculated Reynolds number. 11 、j 12 , and the factor f 11 、f 12 :

[0048] j 11 =0.242(a 11 / D h11 )^(-0.322)*(δ f11 / D h11 )^(0.089)*Re 11 ^(-0.368)

[0049] j 12 =0.242(a 12 / D h12 )^(-0.322)*(δ f12 / D h12 )^(0.089)*Re 12 ^(-0.368)

[0050] f 11 =1.136(a 11 / D h11 )^(-0.781)*(δ f11 / D h11 )^(0.534)*Re 11 ^(-0.198)

[0051] f 12 =1.136(a 12 / D h12 )^(-0.781)*(δf12 / D h12 )^(0.534)*Re 12 ^(-0.198)

[0052] Among them, a 11 、a 12 are the fin heights on the oil cooling side and the cold side respectively; δ 11 , δ 12 are the fin thicknesses on the oil cooling side and the cold side, respectively;

[0053] Step S11: Calculate the heat transfer factor j of the hot side and the cold side respectively according to the structural dimension parameters of each fin on the cold and hot sides of the radiator and the calculated Reynolds number. 21 、j 22 , and the friction factor f 21 、f 22 :

[0054] j 21 =0.242(a 21 / D h21 )^(-0.322)*(δ 21 / D h21 )^(0.089)*Re 21 ^(-0.368)

[0055] j 22 =0.242(a 22 / D h22 )^(-0.322)*(δ 22 / D h22 )^(0.089)*Re 22 ^(-0.368)

[0056] f 21 =1.136(a 21 / D h21 )^(-0.781)*(δ 21 / D h21 )^(0.534)*Re 21 ^(-0.198)

[0057] f 22 =1.136(a 22 / D h22 )^(-0.781)*(δ 22 / D h22 )^(0.534)*Re 22 ^(-0.198)

[0058] Among them, a 21 、a 22are the fin heights on the water cooling side and the cooling side respectively; δ 21 , δ 22 are the fin thicknesses on the water cooling and cooling sides, respectively;

[0059] Step S12: Calculate the mass flow rate G of the working medium on the oil heat dissipation side and the cold side respectively according to the flow rate of the working medium on the cold and hot sides of the oil radiator and the water radiator and the free flow area of ​​each channel. 11 , G 12 , calculate the working fluid mass flow rate G on the water cooling side and the cold side respectively 21 , G 22 :

[0060]

[0061]

[0062]

[0063]

[0064] Among them, m 12 Indicates the cooling air volume through the oil radiator and water radiator, m w Indicates the water pump flow rate on the water cooling side, m 0 Indicates the oil flow rate on the oil cooling side, F 1h Indicates the free flow area on the oil cooling side, F 1C Indicates the free flow area on the cold side of the oil radiator, F 2h Indicates the free flow area on the water cooling side, F 2C Indicates the free flow area on the cold side of the water radiator;

[0065] Step S13: Calculate the heat transfer coefficient α of the oil heat dissipation side and the cold side respectively according to the physical parameters of the working fluids on the cold and hot sides of the oil radiator and the water radiator, combined with the calculated j factor and mass flow rate 11 , α 12 , calculate the heat transfer coefficient α of the water cooling side and the cold side respectively 21 , α 22 :

[0066]

[0067]

[0068]

[0069]

[0070] Among them, c p11 、c p12 、c p21 and c p22They are the constant pressure specific heat capacity of the working fluid on the oil heat dissipation side, the constant pressure specific heat capacity of the working fluid on the oil heat dissipation cooling side, the constant pressure specific heat capacity of the working fluid on the water heat dissipation cooling side, and the constant pressure specific heat capacity of the working fluid on the water heat dissipation cooling side; Pr 11 , Pr 12 , Pr 21 and Pr 22 They are the Prandtl number of the working fluid on the oil heat dissipation side, the Prandtl number of the working fluid on the oil heat dissipation side, the Prandtl number of the working fluid on the water heat dissipation side, and the Prandtl number of the working fluid on the water heat dissipation side;

[0071] Step S14: Calculate the fin efficiency η of the oil heat dissipation side and the cold side according to the heat transfer coefficients and structural parameters of the cold and hot sides of the oil radiator and water radiator, respectively. f11 , η f12 ; Calculate the fin efficiency η on the water cooling side and the cooling side respectively f21 , η f22 :

[0072]

[0073]

[0074]

[0075]

[0076] Among them, H 11 , H 12 , H 21 and H 22 are the wing heights of the oil cooling side, the cold side and the water cooling side, the cold side; P 11 , P 12 , P 21 and P 22 are the fin cross-section perimeters of the oil cooling side, the cold side and the water cooling side, the cold side; λ 11 , 12 , 21 and λ 22 are the thermal conductivity of the fins on the oil cooling side, the cold side and the water cooling side, the cold side; S 11 , S 12 , S 21 and S 22 are the cross-sectional areas of the fins on the oil cooling side, the cold side and the water cooling side, the cold side;

[0077] Step S15: Calculate the heat dissipation Q of the oil radiator based on the heat transfer coefficients and structural parameters of the cold and hot sides of the oil radiator, combined with the calculated temperature difference between the cold and hot sides and the fin efficiency. 1s , compare the oil heat dissipation Q assumed in step S3 1j The calculated Q 1s , if |Q 1s -Q1j |<0.01kW, then step S3 is assumed to be correct, Q 1s This is the calculation result of the heat dissipation capacity of the oil radiator. Conversely, re-assume:

[0078]

[0079] Step S16: Calculate the heat dissipation Q of the water radiator based on the heat transfer coefficients and structural parameters of the cold and hot sides of the water radiator, combined with the calculated temperature difference between the cold and hot sides and the fin efficiency. 2s , compare the water heat dissipation Q assumed in step S3 2j The calculated Q 2s , if |Q 2s -Q 2j |<0.01kW, then step S3 is assumed to be correct, Q 2s This is the calculation result of the heat dissipation capacity of the water radiator. Conversely, re-assume:

[0080]

[0081] Step S17: Based on the calculation results of the f factors of the cold and hot sides of the oil radiator and the water radiator, combined with the structural parameters and physical parameters of the cold and hot sides of the oil radiator and the water radiator, the working medium flow resistance Δp of the hot side and the cold side of the oil radiator is calculated respectively. 11 , Δp 12 , calculate the working fluid flow resistance Δp on the hot side and cold side of the water radiator respectively 21 , Δp 22

[0082]

[0083]

[0084]

[0085]

[0086] Among them, L 11 , L 12 , L 21 and L 22 are the lengths of the working medium flow direction on the oil heat dissipation side, the cold side, the water heat dissipation side and the cold side respectively;

[0087] Step S18: Since the oil radiator and the water radiator are first arranged in series and then connected in parallel with the intercooler, the cooling wind resistance Δp on the cold side of the intercooler 32 Equal to the total resistance of cooling air passing through the oil radiator and water radiator:

[0088] Δp 32 =Δp 12 +Δp 22

[0089] Step S19: Based on the f factor f on the cold side of the intercooler 32 , cold side Reynolds number Re 32 , Cooling wind resistance Δp 32 , the cooling air velocity u on the cold side of the intercooler can be inferred 32 :

[0090] f 32 =1.136(a 32 / D h32 )^(-0.781)*(δ f32 / D h32 )^(0.534)*Re 32 ^(-0.198)

[0091]

[0092]

[0093]

[0094] Among them, ρ 32 is the density of cooling air on the cold side of the intercooler; μ 32 is the dynamic viscosity of the cooling air on the cold side of the intercooler; D h32 , L 32 、a 32 and δ 32 They are the hydraulic diameter of the cold side fin of the intercooler, the cold side working medium flow length, the fin height and the fin thickness;

[0095] Step S20: Calculate the cooling air volume m on the cold side of the intercooler based on the structural parameters of the intercooler and the obtained cooling air velocity on the cold side. 3 :

[0096] m 3 =ρ 32 u 32 F 3c

[0097] Among them, ρ 32 is the density of cooling air on the cold side of the intercooler; μ 32 is the dynamic viscosity of the cooling air on the cold side of the intercooler, F 3c Indicates the free flow area on the cold side of the intercooler;

[0098] Step S21: Calculate the total cooling air volume m passing through the power system heat dissipation assembly based on the assumed cooling air volume of the oil radiator and water radiator on the cold side and the intercooler on the cold side calculated by reverse calculation. a ; Input the resistance data Δp of cooling air passing through the power system's power compartment and grille other, calculate the total cooling wind resistance Δp through the power system heat dissipation assembly a :

[0099] m a =m 12 +m 3

[0100] Δp a =Δp 12 +Δp 22 +Δp other =Δp 32 +Δp other

[0101] Among them, Δp 32 Indicates the cooling wind resistance on the cold side of the intercooler, Δp 12 Indicates the cooling wind resistance on the cooling side of the oil radiator, Δp 22 Indicates the cooling wind resistance on the water radiator cooling side, m 12 Indicates the cooling air volume through the oil radiator and water radiator, m 3 Indicates the cooling air volume passing through the intercooler;

[0102] Step S22: The cooling air is sucked into the power system heat dissipation assembly by the fan, and the static pressure and air volume need to satisfy the characteristic curve of the fan. Assuming that there are x fans, it is determined whether the total cooling air volume / x calculated by the air volume of the oil radiator and the water radiator assumed in step S3 and the total cooling air resistance satisfy the characteristic curve. If so, the assumption in step S3 is correct and the calculation continues. Otherwise, the cooling air volume through the oil radiator and the water radiator in step S3 is re-assumed.

[0103] Step S23: Assume that the heat dissipation of the intercooler is Q 3j , calculate the cooling air outlet temperature T on the cold side of the intercooler 32 ″:

[0104]

[0105] Among them, T a Indicates the inlet temperature of cooling air; Q 3j Indicates the heat dissipation of the intercooler; C 3a Indicates the specific heat capacity of the cooling air on the cold side of the intercooler; m 3 Indicates the cooling air volume on the cold side of the intercooler;

[0106] Step S24: Calculate the qualitative temperature of each working fluid based on the inlet and outlet temperatures of the cold and hot sides of the intercooler. The qualitative temperature of the hot side of the intercooler is T 31 , intercooler cold side cooling air qualitative temperature T 32 :

[0107]

[0108]

[0109] Step S25: Calculate the P of the intercooler according to the inlet and outlet temperatures of the intercooler 3 , R 3 Value, check the PR diagram to get the temperature difference correction coefficient n 3 :

[0110]

[0111]

[0112] Among them, T 32 ″Intercooler cold side cooling air outlet temperature, T 31 ′ represents the intercooler hot side inlet temperature, T 31 ″ represents the intercooler hot side outlet temperature, T' 32 Indicates the cooling air inlet temperature on the cold side of the intercooler;

[0113] Step S26: Based on the temperature difference correction coefficient n 3 , calculate the temperature difference ΔT between the cold and hot sides of the intercooler 3 :

[0114]

[0115] Step S27: According to the qualitative temperature of each working fluid on the cold and hot sides of the intercooler, determine the physical parameters of each working fluid, and calculate the working fluid flow rate u on the hot and cold sides of the intercooler respectively. 31 、u 32 :

[0116]

[0117]

[0118] Among them, ρ q , 32 They are the density of the air on the hot side of the intercooler and the density of the cooling air on the cold side of the intercooler;

[0119] Step S28: According to the qualitative temperature of each working fluid on the cold and hot sides of the intercooler, determine the physical parameters of each working fluid, and calculate the working fluid flow Reynolds number Re on the hot and cold sides of the intercooler respectively in combination with the obtained working fluid flow rate. 31 、Re 32 :

[0120]

[0121]

[0122] Among them, μ 31 , μ32 They are the dynamic viscosity of the air on the hot side of the intercooler and the dynamic viscosity of the cooling air on the cold side of the intercooler;

[0123] Step S29: Calculate the j factor j of the hot side and the cold side respectively according to the structural dimension parameters of each fin on the cold side and the hot side of the intercooler and the calculated Reynolds number 31 、j 32 , and the factor f 31 、f 32 :

[0124] j 31 =0.242(a 31 / D h31 )^(-0.322)*(δ 31 / D h31 )^(0.089)*Re 31 ^(-0.368)

[0125]

[0126] f 31 =1.136(a 31 / D h31 )^(-0.781)*(δ 31 / D h31 )^(0.534)*Re 31 ^(-0.198)

[0127]

[0128] Among them, a 31 is the fin height on the hot side of the intercooler; δ 31 is the thickness of the fins on the hot side of the intercooler;

[0129] Step S30: Calculate the working medium mass flow rate G on the hot side and the cold side of the intercooler according to the flow rate of the working medium on the cold and hot sides of the intercooler and the free flow area of ​​each channel. 31 , G 32 :

[0130]

[0131]

[0132] In the formula, m 3 Indicates the cooling air volume on the cold side of the intercooler, m q Indicates the air intake volume on the hot side of the intercooler, F 3h It represents the free flow area on the hot side of the intercooler;

[0133] Step S31: Calculate the heat transfer coefficient α of the hot side and the cold side of the intercooler according to the physical parameters of the working fluid on the cold and hot sides of the intercooler, combined with the calculated j factor and mass flow rate. 31 , α 32 :

[0134]

[0135]

[0136] Among them, c p31 、c p32 They are the constant pressure specific heat capacity of the working fluid on the hot side of the intercooler and the constant pressure specific heat capacity of the working fluid on the cold side of the intercooler; Pr 31 , Pr 32 They are the Prandtl number of the working fluid on the hot side of the intercooler and the Prandtl number of the working fluid on the cold side of the intercooler respectively;

[0137] Step S32: Calculate the fin efficiency η of the hot side and the cold side of the intercooler according to the heat transfer coefficient and structural parameters of the cold and hot sides of the intercooler f31 , η f32 :

[0138]

[0139]

[0140] Among them, H 31 , H 32 are the wing heights of the hot and cold sides of the intercooler; P 31 , P 32 are the fin cross-section perimeters of the hot and cold sides of the intercooler; 31 , 32 are the thermal conductivity of the fins on the hot and cold sides of the intercooler, W·m -1 ·K -1 ; S 31 , S 32 are the cross-sectional areas of the fins on the hot and cold sides of the intercooler, respectively;

[0141] Step S33: Calculate the heat dissipation Q of the intercooler based on the heat transfer coefficients and structural parameters of the cold and hot sides of the intercooler and the calculated temperature difference between the cold and hot sides. 3s , compare the intercooler heat dissipation Q assumed in step S23 3j The calculated Q 3s , if |Q 3s -Q 3j |<0.01kW, then step S23 assumes that it is correct, Q 3s This is the calculation result of the heat dissipation capacity of the intercooler. On the contrary, re-assume:

[0142]

[0143] Among them, α 31 Indicates the heat transfer coefficient of the hot side of the intercooler; A 3h represents the heat exchange area on the hot side of the intercooler, α 32 Indicates the heat transfer coefficient of the cold side of the intercooler; A 3c Indicates the heat exchange area on the cold side of the intercooler; ΔT 3 Indicates the temperature difference between the cold and hot sides of the intercooler;

[0144] Step S34: Calculate the hot side working medium flow resistance Δp of the intercooler according to the calculation result of the f factor of the hot side of the intercooler and the hot side structural parameters and physical parameters of the intercooler. 31 :

[0145]

[0146] Among them, L 31 is the length of the hot side of the intercooler in the direction of working fluid flow, D h31 represents the hydraulic diameter of the hot side fin of the intercooler, ρ q Indicates the density of the air on the hot side of the intercooler, μ 31 Indicates the dynamic viscosity of the air on the hot side of the intercooler;

[0147] Step S35: Repeat the iteration of step S3 and step S23, verify step S15, step S16, step 22, and step S33, and finally calculate the heat balance result of the heat dissipation assembly, including the heat dissipation of the oil radiator, water radiator and intercooler, the cooling air flow rate, and the cold side and hot side resistance data of each radiator.

[0148] Preferably, the common heat dissipation assembly includes an intercooler, an oil radiator, a water radiator and a fan.

[0149] Preferably, the oil radiator is referred to as oil radiator, and the water radiator is referred to as water radiator.

[0150] The beneficial effects of the heat balance calculation method of the series-parallel type heat dissipation assembly structure of the present invention are as follows:

[0151] 1. The heat dissipation assembly calculation of the series-parallel arrangement structure is realized.

[0152] 2. Solved the problem of matching the cooling air volume and resistance of the heat dissipation assembly.

[0153] 3. Multiple iterations are performed to achieve accurate thermal balance calculation of the heat dissipation assembly, thus improving the accuracy of theoretical calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0154] Figure 1 This is a layout diagram of the heat dissipation assembly of the present invention.

[0155] Figure 2It is a simplified schematic diagram of the heat dissipation assembly of the present invention.

[0156] Figure 3 It is a matching flow chart of the present invention.

[0157] Figure 4 It is a calculation flow chart of the present invention.

[0158] Figure numerals: 1 - oil radiator, 2 - water radiator, 3 - intercooler. DETAILED DESCRIPTION

[0159] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0160] The series-parallel type heat dissipation assembly structure includes an oil radiator, a water radiator and an intercooler; the water radiator is arranged at the bottom of the oil radiator, and the intercooler is arranged at the other end of the water radiator.

[0161] A series-parallel type heat dissipation assembly heat balance calculation method of this embodiment includes the following steps:

[0162] Step S1: input the core size, fin type, and fin size and structure parameters of each radiator in the heat dissipation assembly, where the subscripts c and h represent the low temperature side and the high temperature side of the radiator, respectively;

[0163] Step S2: Input the known parameters of the oil flowing through each radiator: oil cooling side oil flow m o , Water pump flow rate on water cooling side m w , Intercooler hot side intake volume m q , Oil inlet temperature T on the oil cooling side 11 ', water inlet temperature T on the water cooling side 21 '、Intercooler hot side inlet temperature T 31 '、Intercooler hot side outlet temperature T 31 ″、Inlet temperature of cooling air T a ;

[0164] Step S3: Assume that the cooling air volume m passing through the oil radiator and the water radiator side 12 , Assume that the heat dissipation of the oil radiator is Q 1j , Assume that the heat dissipation of the water radiator is Q 2j , calculate the oil outlet temperature T on the oil cooling side 11 ″、Oil outlet temperature on the oil cooling side T 12 ″:

[0165]

[0166]

[0167] Among them, c o 、c 12 are the specific heat capacities of the engine oil and the cooling air on the cooling side of the oil radiator;

[0168] Step S4: Water outlet temperature T at the water cooling side 21 ″、Inlet temperature of cooling air on the cooling side of the water radiator T 22 '、Inlet temperature of cooling air on the cooling side of the water radiator T 22 ″:

[0169]

[0170] T 22 ′=T 12 ″

[0171]

[0172] Among them, c w 、c 22 are the specific heat capacities of water and cooling air on the water cooling side;

[0173] Step S5: Calculate the qualitative temperature of each working fluid based on the inlet and outlet temperatures of the oil radiator and the water radiator on the cold side and the hot side. The qualitative temperature is used to determine the physical parameters of each working fluid. The qualitative temperature of the oil on the oil radiator side is T 11 , Cooling air qualitative temperature T on the cooling side of the oil radiator 12 , water qualitative temperature T on the water cooling side 21 , Qualitative temperature of cooling air on the cooling side of water radiator T 22 :

[0174]

[0175]

[0176]

[0177]

[0178] Step S6: Calculate the P of the oil radiator according to the inlet and outlet temperatures of the oil radiator. 1 , R 1 Value, check the PR diagram to get the temperature difference correction coefficient n 1 ; Calculate the P of the water radiator according to the inlet and outlet temperatures of the water radiator 2 , R 2 Value, check the PR diagram to get the temperature difference correction coefficient n 2 :

[0179]

[0180]

[0181]

[0182]

[0183] Where, T' 21 Indicates the inlet temperature of the water cooling side; T' 12 Indicates the inlet temperature of the oil radiator on the cold side; T” 12 Indicates the outlet temperature of the oil radiator on the cold side; T” 21 Indicates the outlet temperature of the water cooling side; T” 11 Indicates the outlet temperature of the oil heat dissipation side; T' 11 Indicates the inlet temperature of the oil heat dissipation side;

[0184] Step S7: Based on the temperature difference correction coefficient n 1 and n 2 , calculate the temperature difference ΔT on the cold and hot sides of the oil and water radiators respectively 1 , ΔT 2 , calculated using the average logarithmic temperature difference formula:

[0185]

[0186]

[0187] Step S8: According to the qualitative temperature of each working medium on the cold and hot sides of the oil radiator and the water radiator, determine the physical parameters of each working medium, and calculate the working medium flow rate u on the oil heat dissipation side and the cold side respectively. 11 、u 12 , calculate the working fluid flow rate u on the water cooling side and the cold side respectively 21 、u 22 ;

[0188]

[0189]

[0190]

[0191]

[0192] Among them, ρ o , 12 , w and ρ 22 They are the density of the oil on the oil heat dissipation side, the density of the cooling air on the oil heat dissipation side, the density of the water on the water heat dissipation side, and the density of the cooling air on the water heat dissipation side;

[0193] Step S9: According to the qualitative temperature of each working fluid on the cold and hot sides of the oil radiator and the water radiator, determine the physical parameters of each working fluid, and calculate the working fluid flow Reynolds number Re on the oil heat dissipation side and the cold side respectively in combination with the obtained working fluid flow rate 11 、Re 12 , calculate the Reynolds number Re of the working fluid flow on the water cooling side and the cold side respectively 21 、Re 22 :

[0194]

[0195]

[0196]

[0197]

[0198] Among them, D h11 , D h12 , D h21 and D h22 are the hydraulic diameter of the fin on the oil heat dissipation side, the hydraulic diameter of the fin on the oil heat dissipation cooling side, the hydraulic diameter of the fin on the water heat dissipation side, and the hydraulic diameter of the fin on the water heat dissipation cooling side; μ 11 , μ 12 , μ 21 and μ 22 They are the dynamic viscosity of the oil on the oil heat dissipation side, the dynamic viscosity of the cooling air on the oil heat dissipation side, the dynamic viscosity of the water on the water heat dissipation side, and the dynamic viscosity of the cooling air on the water heat dissipation side;

[0199] Step S10: Calculate the j factor j of the hot side and the cold side respectively according to the structural dimension parameters of each fin on the cold side and the hot side of the oil radiator and the calculated Reynolds number. 11 、j 12 , and the factor f 11 、f 12 ;

[0200] j 11 =0.242(a 11 / D h11 )^(-0.322)*(δ f11 / D h11 )^(0.089)*Re 11 ^(-0.368)

[0201] j 12 =0.242(a 12 / D h12 )^(-0.322)*(δ f12 / D h12 )^(0.089)*Re 12^(-0.368)

[0202] f 11 =1.136(a 11 / D h11 )^(-0.781)*(δ f11 / D h11 )^(0.534)*Re 11 ^(-0.198)

[0203] f 12 =1.136(a 12 / D h12 )^(-0.781)*(δ f12 / D h12 )^(0.534)*Re 12 ^(-0.198)

[0204] Among them, a 11 、a 12 are the fin heights on the oil cooling side and the cold side respectively; δ 11 , δ 12 are the fin thicknesses on the oil cooling side and the cold side, respectively;

[0205] Step S11: Calculate the heat transfer factor j of the hot side and the cold side respectively according to the structural dimension parameters of each fin on the cold and hot sides of the radiator and the calculated Reynolds number. 21 、j 22 , and the friction factor f 21 、f 22 :

[0206] j 21 =0.242(a 21 / D h21 )^(-0.322)*(δ 21 / D h21 )^(0.089)*Re 21 ^(-0.368)

[0207] j 22 =0.242(a 22 / D h22 )^(-0.322)*(δ 22 / D h22 )^(0.089)*Re 22 ^(-0.368)

[0208] f 21 =1.136(a 21 / D h21 )^(-0.781)*(δ 21 / D h21)^(0.534)*Re 21 ^(-0.198)

[0209] f 22 =1.136(a 22 / D h22 )^(-0.781)*(δ 22 / D h22 )^(0.534)*Re 22 ^(-0.198)

[0210] Among them, a 21 、a 22 are the fin heights on the water cooling side and the cooling side respectively; δ 21 , δ 22 are the fin thicknesses on the water cooling and cooling sides, respectively;

[0211] Step S12: Calculate the mass flow rate G of the working medium on the oil heat dissipation side and the cold side respectively according to the flow rate of the working medium on the cold and hot sides of the oil radiator and the water radiator and the free flow area of ​​each channel. 11 , G 12 , calculate the working fluid mass flow rate G on the water cooling side and the cold side respectively 21 , G 22 :

[0212]

[0213]

[0214]

[0215]

[0216] Among them, m 12 Indicates the cooling air volume through the oil radiator and water radiator, m w Indicates the water pump flow rate on the water cooling side, m 0 Indicates the oil flow rate on the oil cooling side, F 1h Indicates the free flow area on the oil cooling side, F 1C Indicates the free flow area on the cold side of the oil radiator, F 2h Indicates the free flow area on the water cooling side, F 2C Indicates the free flow area on the cold side of the water radiator;

[0217] Step S13: Calculate the heat transfer coefficient α of the oil heat dissipation side and the cold side respectively according to the physical parameters of the working fluids on the cold and hot sides of the oil radiator and the water radiator, combined with the calculated j factor and mass flow rate 11 , α 12 , calculate the heat transfer coefficient α of the water cooling side and the cold side respectively 21 , α 22 :

[0218]

[0219]

[0220]

[0221]

[0222] Among them, c p11 、c p12 、c p21 and c p22 They are the constant pressure specific heat capacity of the working fluid on the oil heat dissipation side, the constant pressure specific heat capacity of the working fluid on the oil heat dissipation cooling side, the constant pressure specific heat capacity of the working fluid on the water heat dissipation cooling side, and the constant pressure specific heat capacity of the working fluid on the water heat dissipation cooling side; Pr 11 , Pr 12 , Pr 21 and Pr 22 They are the Prandtl number of the working fluid on the oil heat dissipation side, the Prandtl number of the working fluid on the oil heat dissipation side, the Prandtl number of the working fluid on the water heat dissipation side, and the Prandtl number of the working fluid on the water heat dissipation side;

[0223] Step S14: Calculate the fin efficiency η of the oil heat dissipation side and the cold side according to the heat transfer coefficients and structural parameters of the cold and hot sides of the oil radiator and water radiator, respectively. f11 , η f12 ; Calculate the fin efficiency η on the water cooling side and the cooling side respectively f21 , η f22 :

[0224]

[0225]

[0226]

[0227]

[0228] Among them, H 11 , H 12 , H 21 and H 22 are the wing heights of the oil cooling side, the cold side and the water cooling side, the cold side; P 11 , P 12 , P 21 and P 22 are the fin cross-section perimeters of the oil cooling side, the cold side and the water cooling side, the cold side; λ 11 , 12 , 21 and λ 22 are the thermal conductivity of the fins on the oil cooling side, the cold side and the water cooling side, the cold side; S11 , S 12 , S 21 and S 22 are the cross-sectional areas of the fins on the oil cooling side, the cold side and the water cooling side, the cold side;

[0229] Step S15: Calculate the heat dissipation Q of the oil radiator based on the heat transfer coefficients and structural parameters of the cold and hot sides of the oil radiator, combined with the calculated temperature difference between the cold and hot sides and the fin efficiency. 1s , compare the oil heat dissipation Q assumed in step S3 1j The calculated Q 1s , if |Q 1s -Q 1j |<0.01kW, then step S3 is assumed to be correct, Q 1s This is the calculation result of the heat dissipation capacity of the oil radiator. Conversely, re-assume:

[0230]

[0231] Step S16: Calculate the heat dissipation Q of the water radiator based on the heat transfer coefficients and structural parameters of the cold and hot sides of the water radiator, combined with the calculated temperature difference between the cold and hot sides and the fin efficiency. 2s , compare the water heat dissipation Q assumed in step S3 2j The calculated Q 2s , if |Q 2s -Q 2j |<0.01kW, then step S3 is assumed to be correct, Q 2s This is the calculation result of the heat dissipation capacity of the water radiator. Conversely, re-assume:

[0232]

[0233] Step S17: Based on the calculation results of the f factors of the cold and hot sides of the oil radiator and the water radiator, combined with the structural parameters and physical parameters of the cold and hot sides of the oil radiator and the water radiator, the working medium flow resistance Δp of the hot side and the cold side of the oil radiator is calculated respectively. 11 , Δp 12 , calculate the working fluid flow resistance Δp on the hot side and cold side of the water radiator respectively 21 , Δp 22 :

[0234]

[0235]

[0236]

[0237]

[0238] Among them, L 11 , L12 , L 21 and L 22 are the lengths of the working medium flow direction on the oil heat dissipation side, the cold side, the water heat dissipation side and the cold side respectively;

[0239] Step S18: Since the oil radiator and the water radiator are first arranged in series and then connected in parallel with the intercooler, the cooling wind resistance Δp on the cold side of the intercooler 32 Equal to the total resistance of cooling air passing through the oil radiator and water radiator:

[0240] Δp 32 =Δp 12 +Δp 22

[0241] Step S19: Based on the f factor f on the cold side of the intercooler 32 , cold side Reynolds number Re 32 , Cooling wind resistance Δp 32 , the cooling air velocity u on the cold side of the intercooler can be inferred 32 :

[0242] f 32 =1.136(a 32 / D h32 )^(-0.781)*(δ f32 / D h32 )^(0.534)*Re 32 ^(-0.198)

[0243]

[0244]

[0245]

[0246] Among them, ρ 32 is the density of cooling air on the cold side of the intercooler; μ 32 is the dynamic viscosity of the cooling air on the cold side of the intercooler; D h32 , L 32 、a 32 and δ 32 They are the hydraulic diameter of the cold side fin of the intercooler, the cold side working medium flow length, the fin height and the fin thickness;

[0247] Step S20: Calculate the cooling air volume m on the cold side of the intercooler based on the structural parameters of the intercooler and the obtained cooling air velocity on the cold side. 3 :

[0248] m 3 =ρ 32 u 32 F 3c

[0249] Among them, ρ 32 is the density of cooling air on the cold side of the intercooler; μ 32 is the dynamic viscosity of the cooling air on the cold side of the intercooler, F 3c It represents the free flow area on the cold side of the intercooler;

[0250] Step S21: Calculate the total cooling air volume m passing through the power system heat dissipation assembly based on the assumed cooling air volume of the oil radiator and water radiator on the cold side and the intercooler on the cold side calculated by reverse calculation. a ; Input the resistance data Δp of cooling air passing through the power system's power compartment and grille other , calculate the total cooling wind resistance Δp through the power system heat dissipation assembly a :

[0251] m a =m 12 +m 3

[0252] Δp a =Δp 31 +Δp 32 +Δp other =Δp 3 +Δp other

[0253] Among them, Δp 32 Indicates the cooling wind resistance on the cold side of the intercooler, Δp 12 Indicates the cooling wind resistance on the cooling side of the oil radiator, Δp 22 Indicates the cooling wind resistance on the water radiator cooling side, m 12 Indicates the cooling air volume through the oil radiator and water radiator, m 3 Table of cooling air volume passing through the intercooler;

[0254] Step S22: The cooling air is sucked into the power system heat dissipation assembly by the fan, and the static pressure and air volume need to satisfy the characteristic curve of the fan. Assuming that there are x fans, it is determined whether the total cooling air volume / x calculated by the air volume of the oil radiator and the water radiator assumed in step S3 and the total cooling air resistance satisfy the characteristic curve. If so, the assumption in step S3 is correct and the calculation continues. Otherwise, the cooling air volume through the oil radiator and the water radiator in step S3 is re-assumed.

[0255] Step S23: Assume that the heat dissipation of the intercooler is Q 3j , calculate the cooling air outlet temperature T on the cold side of the intercooler 32 ″:

[0256]

[0257] Among them, T a Indicates the inlet temperature of cooling air; Q3j Indicates the heat dissipation of the intercooler; C 3a Indicates the specific heat capacity of the cooling air on the cold side of the intercooler; m 3 Indicates the cooling air volume on the cold side of the intercooler;

[0258] Step S24: Calculate the qualitative temperature of each working fluid based on the inlet and outlet temperatures of the cold and hot sides of the intercooler. The qualitative temperature of the hot side of the intercooler is T 31 , intercooler cold side cooling air qualitative temperature T 32 :

[0259]

[0260]

[0261] Step S25: Calculate the P of the intercooler according to the inlet and outlet temperatures of the intercooler 3 , R 3 Value, check the PR diagram to get the temperature difference correction coefficient n 3 :

[0262]

[0263]

[0264] Among them, T 32 ″Intercooler cold side cooling air outlet temperature, T 31 ′ represents the intercooler hot side inlet temperature, T 31 ″ represents the intercooler hot side outlet temperature, T' 32 Indicates the cooling air inlet temperature on the cold side of the intercooler;

[0265] Step S26: Based on the temperature difference correction coefficient n 3 , calculate the temperature difference ΔT between the cold and hot sides of the intercooler 3 :

[0266]

[0267] Step S27: According to the qualitative temperature of each working fluid on the cold and hot sides of the intercooler, determine the physical parameters of each working fluid, and calculate the working fluid flow rate u on the hot and cold sides of the intercooler respectively. 31 、u 32 :

[0268]

[0269]

[0270] Among them, ρ q , 32 They are the density of the air on the hot side of the intercooler and the density of the cooling air on the cold side of the intercooler;

[0271] Step S28: According to the qualitative temperature of each working fluid on the cold and hot sides of the intercooler, determine the physical parameters of each working fluid, and calculate the working fluid flow Reynolds number Re on the hot and cold sides of the intercooler respectively in combination with the obtained working fluid flow rate. 31 、Re 32 :

[0272]

[0273]

[0274] Among them, μ 31 , μ 32 They are the dynamic viscosity of the air on the hot side of the intercooler and the dynamic viscosity of the cooling air on the cold side of the intercooler;

[0275] Step S29: Calculate the j factor j of the hot side and the cold side respectively according to the structural dimension parameters of each fin on the cold side and the hot side of the intercooler and the calculated Reynolds number 31 、j 32 , and the factor f 31 、f 32 :

[0276] j 31 =0.242(a 31 / D h31 )^(-0.322)*(δ 31 / D h31 )^(0.089)*Re 31 ^(-0.368)

[0277]

[0278] f 31 =1.136(a 31 / D h31 )^(-0.781)*(δ 31 / D h31 )^(0.534)*Re 31 ^(-0.198)

[0279]

[0280] Among them, a 31 is the fin height on the hot side of the intercooler; δ 31 is the thickness of the fins on the hot side of the intercooler;

[0281] Step S30: Calculate the working medium mass flow rate G on the hot side and the cold side of the intercooler according to the flow rate of the working medium on the cold and hot sides of the intercooler and the free flow area of ​​each channel. 31 , G 32 :

[0282]

[0283]

[0284] In the formula, m 3 Indicates the cooling air volume on the cold side of the intercooler, m q Indicates the air intake volume on the hot side of the intercooler, F 3h It represents the free flow area on the hot side of the intercooler;

[0285] Step S31: Calculate the heat transfer coefficient α of the hot side and the cold side of the intercooler according to the physical parameters of the working fluid on the cold and hot sides of the intercooler, combined with the calculated j factor and mass flow rate. 31 , α 32 :

[0286]

[0287]

[0288] Among them, c p31 、c p32 They are the constant pressure specific heat capacity of the working fluid on the hot side of the intercooler and the constant pressure specific heat capacity of the working fluid on the cold side of the intercooler; Pr 31 , Pr 32 They are the Prandtl number of the working fluid on the hot side of the intercooler and the Prandtl number of the working fluid on the cold side of the intercooler respectively;

[0289] Step S32: Calculate the fin efficiency η of the hot side and the cold side of the intercooler according to the heat transfer coefficient and structural parameters of the cold and hot sides of the intercooler f31 , η f32 :

[0290]

[0291]

[0292] Among them, H 31 , H 32 are the wing heights of the hot and cold sides of the intercooler; P 31 , P 32 are the fin cross-section perimeters of the hot and cold sides of the intercooler; 31 , 32 are the thermal conductivity of the fins on the hot and cold sides of the intercooler, W·m -1 ·K -1 ; S 31 , S 32 are the cross-sectional areas of the fins on the hot and cold sides of the intercooler, respectively;

[0293] Step S33: Calculate the heat dissipation Q of the intercooler based on the heat transfer coefficients and structural parameters of the cold and hot sides of the intercooler and the calculated temperature difference between the cold and hot sides. 3s , compare the intercooler heat dissipation Q assumed in step S23 3j The calculated Q 3s , if |Q 3s -Q 3j |<0.01kW, then step S23 assumes that it is correct, Q 3s This is the calculation result of the heat dissipation capacity of the intercooler. On the contrary, re-assume:

[0294]

[0295] Among them, α 31 Indicates the heat transfer coefficient of the hot side of the intercooler; A 3h represents the heat exchange area on the hot side of the intercooler, α 32 Indicates the heat transfer coefficient of the cold side of the intercooler; A 3c Indicates the heat exchange area on the cold side of the intercooler; ΔT 3 Indicates the temperature difference between the cold and hot sides of the intercooler;

[0296] Step S34: Calculate the hot side working medium flow resistance Δp of the intercooler according to the calculation result of the f factor of the hot side of the intercooler and the hot side structural parameters and physical parameters of the intercooler. 31 :

[0297]

[0298] Among them, L 31 is the length of the hot side of the intercooler in the direction of working fluid flow, D h31 represents the hydraulic diameter of the hot side fin of the intercooler, ρ q Indicates the density of the air on the hot side of the intercooler, μ 31 Indicates the dynamic viscosity of the air on the hot side of the intercooler;

[0299] Step S35: Repeat the iteration of step S3 and step S23, verify step S15, step S16, step 22, and step S33, and finally calculate the heat balance result of the heat dissipation assembly, including the heat dissipation of the oil radiator, water radiator and intercooler, the cooling air flow rate, and the cold side and hot side resistance data of each radiator.

[0300] The common heat dissipation assembly of this embodiment includes an intercooler, an oil radiator, a water radiator and a fan.

[0301] The oil radiator of this embodiment is referred to as oil radiator, and the water radiator is referred to as water radiator.

[0302] When this embodiment is implemented, a heat balance calculation method for matching fan characteristics of a series-parallel type heat dissipation assembly is arranged as follows: Figure 1 As shown, Figure 2 To simplify the diagram, the flow matching process is as follows: Figure 3 As shown, the heat balance calculation method is as follows Figure 4 As shown, it includes:

[0303] (1) Input the core size, fin type, and fin size and structural parameters of each radiator in the heat dissipation assembly, and calculate the heat exchange area (A) on the cold side and hot side of each radiator. c , A h ), free circulation area (F c 、F h ), hydraulic diameter (D h ) and other parameters for subsequent calculation input, where the subscripts c and h represent the low temperature side (hereinafter referred to as the cold side) and the high temperature side (hereinafter referred to as the hot side) of the radiator, respectively;

[0304] (2) The heat dissipation assembly consists of an intercooler, an oil radiator (hereinafter referred to as the oil radiator), a water radiator (hereinafter referred to as the water radiator) and a fan. The oil radiator and the water radiator are connected in series and then in series with the intercooler. The known parameters passing through each radiator are input: Oil flow rate m on the oil radiator side o , Water pump flow rate on water cooling side m w , Intercooler hot side intake volume m q , kg / s; Oil inlet temperature on the oil cooling side T 11 ', water inlet temperature T on the water cooling side 21 '、Intercooler hot side inlet temperature T 31 '、Intercooler hot side outlet temperature T 31 ″、Inlet temperature of cooling air T a ,℃;

[0305] (3) Assume that the cooling air volume m passing through the oil and water radiators is 12 , kg / s;

[0306] (4) Assume that the heat dissipation of the oil radiator is Q 1j , kW;

[0307] (5) Assume that the heat dissipation of the water radiator is Q 2j , kW;

[0308] (6) Calculate the oil outlet temperature T on the oil cooling side 11 ″、Cooling air outlet temperature T on the cooling side of the oil radiator 12 ″, °C;

[0309]

[0310]

[0311] Among them, c o 、c12 are the specific heat capacities of the oil and the cooling air on the cooling side of the oil radiator, kJ·kg -1 ·K -1 ;

[0312] (7) Water outlet temperature T on the water cooling side 21 ″、Inlet temperature of cooling air on the cooling side of the water radiator T 22 '、Inlet temperature of cooling air on the cooling side of the water radiator T 22 ″, °C;

[0313]

[0314] T 22 ′=T 12 ″

[0315]

[0316] Among them, c w 、c 22 are the specific heat capacities of water and cooling air on the water cooling side, kJ·kg -1 ·K -1 ;

[0317] (8) The qualitative temperature of each working fluid is calculated based on the inlet and outlet temperatures of the cold and hot sides of the oil radiator and water radiator. The qualitative temperature is used to determine the physical properties of each working fluid. The qualitative temperature of the oil on the oil radiator side is T 11 , Cooling air qualitative temperature T on the cooling side of the oil radiator 12 , water qualitative temperature T on the water cooling side 21 , Qualitative temperature of cooling air on the cooling side of water radiator T 22 :

[0318]

[0319]

[0320]

[0321]

[0322] (9) Calculate the P of the oil radiator based on the inlet and outlet temperatures of the oil radiator. 1 , R 1 Value, check the PR diagram to get the temperature difference correction coefficient n 1 ; Calculate the P of the water radiator according to the inlet and outlet temperatures of the water radiator 2 , R 2 Value, check the PR diagram to get the temperature difference correction coefficient n 2 :

[0323]

[0324]

[0325]

[0326]

[0327] (10) Based on the temperature difference correction coefficient n 1 and n 2 , calculate the temperature difference ΔT on the cold and hot sides of the oil and water radiators respectively 1 , ΔT 2 , ℃, calculated using the average logarithmic temperature difference formula:

[0328]

[0329]

[0330] (11) According to the qualitative temperature of each working fluid on the cold and hot sides of the oil and water radiators, determine the physical parameters of each working fluid, and calculate the working fluid flow rate u on the oil heat dissipation side and the cold side respectively. 11 、u 12 , kg / s, calculate the working fluid flow rate u on the water cooling side and the cold side respectively 21 、u 22 , kg / s:

[0331]

[0332]

[0333]

[0334]

[0335] Among them, ρ o , 12 , w and ρ 22 They are the density of the oil on the oil cooling side, the density of the cooling air on the oil cooling side, the density of the water on the water cooling side, and the density of the cooling air on the water cooling side, kg / m 3 ;

[0336] (12) According to the qualitative temperature of each working fluid on the cold and hot sides of the oil and water radiators, the physical parameters of each working fluid are determined. Combined with the obtained working fluid flow rate, the working fluid flow Reynolds number Re on the oil heat dissipation side and the cold side is calculated respectively. 11 、Re 12 , calculate the Reynolds number Re of the working fluid flow on the water cooling side and the cold side respectively 21 、Re 22 :

[0337]

[0338]

[0339]

[0340]

[0341] Among them, D h11 , D h12 , D h21 and D h22 are the hydraulic diameter of the fin on the oil heat dissipation side, the hydraulic diameter of the fin on the oil heat dissipation cooling side, the hydraulic diameter of the fin on the water heat dissipation side, and the hydraulic diameter of the fin on the water heat dissipation cooling side; μ 11 , μ 12 , μ 21 and μ 22 They are the dynamic viscosity of the oil on the oil heat dissipation side, the dynamic viscosity of the cooling air on the oil heat dissipation side, the dynamic viscosity of the water on the water heat dissipation side, and the dynamic viscosity of the cooling air on the water heat dissipation side;

[0342] (13) According to the structural dimension parameters of the fins on the cold and hot sides of the oil radiator, combined with the calculated Reynolds number, the j factor j on the hot and cold sides is calculated respectively. 11 、j 12 , and the factor f 11 、f 12 This patent takes the oil radiator with serrated fins on both the cold and hot sides as an example, and uses the heat transfer and pressure drop test data of serrated fins to fit the commonly used relationship:

[0343] j 11 =0.242(a 11 / D h11 )^(-0.322)*(δ f11 / D h11 )^(0.089)*Re 11 ^(-0.368)

[0344] j 12 =0.242(a 12 / D h12 )^(-0.322)*(δ f12 / D h12 )^(0.089)*Re 12 ^(-0.368)

[0345] f 11 =1.136(a 11 / D h11 )^(-0.781)*(δ f11 / D h11 )^(0.534)*Re 11 ^(-0.198)

[0346] f 12 =1.136(a 12 / D h12 )^(-0.781)*(δ f12 / D h12 )^(0.534)*Re 12 ^(-0.198)

[0347] Among them, a 11 、a 12 are the fin heights on the oil cooling side and the cold side, mm; δ 11 , δ 12 are the fin thickness on the oil cooling side and the cold side, mm;

[0348] (14) According to the structural dimension parameters of the fins on the cold and hot sides of the radiator and the calculated Reynolds number, the heat transfer factor (j factor) of the hot and cold sides is calculated respectively. 21 、j 22 , and the friction coefficient (f factor) f 21 、f 22 This patent takes the zigzag fins on both the cold and hot sides of the water radiator as an example:

[0349] j 21 =0.242(a 21 / D h21 )^(-0.322)*(δ 21 / D h21 )^(0.089)*Re 21 ^(-0.368)

[0350] j 22 =0.242(a 22 / D h22 )^(-0.322)*(δ 22 / D h22 )^(0.089)*Re 22 ^(-0.368)

[0351] f 21 =1.136(a 21 / D h21 )^(-0.781)*(δ 21 / D h21 )^(0.534)*Re 21 ^(-0.198)

[0352] f 22 =1.136(a 22 / D h22 )^(-0.781)*(δ 22 / D h22)^(0.534)*Re 22 ^(-0.198)

[0353] Among them, a 21 、a 22 are the fin heights on the water cooling side and the cooling side respectively; δ 21 , δ 22 are the fin thicknesses on the water cooling and cooling sides, respectively;

[0354] (15) According to the flow rate of the working fluid on the cold and hot sides of the oil and water radiators, combined with the free flow area of ​​each channel, the mass flow rate G of the working fluid on the oil heat dissipation side and the cold side is calculated respectively. 11 , G 12 , calculate the working fluid mass flow rate G on the water cooling side and the cold side respectively 21 , G 22 :

[0355]

[0356]

[0357]

[0358]

[0359] (16) According to the physical parameters of the working fluids on the cold and hot sides of the oil and water radiators, combined with the calculated j factor and mass flow rate, the heat transfer coefficient α of the oil cooling side and the cold side is calculated respectively. 11 , α 12 , calculate the heat transfer coefficient α of the water cooling side and the cold side respectively 21 , α 22 :

[0360]

[0361]

[0362]

[0363]

[0364] where c p11 、c p12 、c p21 and c p22 They are the constant pressure specific heat capacity of the working fluid on the oil heat dissipation side, the constant pressure specific heat capacity of the working fluid on the oil heat dissipation cooling side, the constant pressure specific heat capacity of the working fluid on the water heat dissipation cooling side, and the constant pressure specific heat capacity of the working fluid on the water heat dissipation cooling side; Pr 11 , Pr 12 , Pr 21 and Pr 22They are the Prandtl number of the working fluid on the oil heat dissipation side, the Prandtl number of the working fluid on the oil heat dissipation side, the Prandtl number of the working fluid on the water heat dissipation side, and the Prandtl number of the working fluid on the water heat dissipation side;

[0365] (17) According to the heat transfer coefficients and structural parameters of the cold and hot sides of the oil and water radiators, the fin efficiency η of the oil heat dissipation side and the cold side is calculated respectively. f11 , η f12 ; Calculate the fin efficiency η on the water cooling side and the cooling side respectively f21 , η f22 :

[0366]

[0367]

[0368]

[0369]

[0370] Among them, H 11 , H 12 , H 21 and H 22 are the wing heights of the oil cooling side, the cold side and the water cooling side, the cold side; P 11 , P 12 , P 21 and P 22 are the fin cross-section perimeters of the oil cooling side, the cold side and the water cooling side, the cold side; λ 11 , 12 , 21 and λ 22 are the thermal conductivity of the fins on the oil cooling side, the cold side and the water cooling side, the cold side; S 11 , S 12 , S 21 and S 22 are the cross-sectional areas of the fins on the oil cooling side, the cold side and the water cooling side, the cold side;

[0371] (18) Based on the heat transfer coefficients and structural parameters of the cold and hot sides of the oil radiator, combined with the calculated temperature difference between the cold and hot sides and the fin efficiency, the heat dissipation Q of the oil radiator is calculated. 1s , compare the oil heat dissipation Q assumed in step (3) 1j The calculated Q 1s , if |Q 1s -Q 1j |<0.01kW, then step (3) is assumed to be correct, Q 1s This is the calculation result of the heat dissipation capacity of the oil radiator. Conversely, re-assume:

[0372]

[0373] (19) According to the heat transfer coefficient and structural parameters of the cold and hot sides of the water radiator, combined with the calculated temperature difference between the cold and hot sides and the fin efficiency, the heat dissipation Q of the water radiator is calculated. 2s , compare the water heat dissipation Q assumed in step (4) 2j The calculated Q 2s , if |Q 2s -Q 2j |<0.01kW, then step (4) is assumed to be correct, Q 2s This is the calculation result of the heat dissipation capacity of the water radiator. Conversely, re-assume:

[0374]

[0375] (20) According to the calculation results of the f factor on the cold and hot sides of the oil and water radiators, combined with the structural parameters and physical parameters of the cold and hot sides of the oil and water radiators, the working fluid flow resistance Δp on the hot and cold sides of the oil radiator is calculated respectively. 11 , Δp 12 , Pa, respectively calculate the working fluid flow resistance Δp on the hot side and cold side of the water radiator 21 , Δp 22 ,Pa:

[0376]

[0377]

[0378]

[0379]

[0380] Among them, L 11 , L 12 , L 21 and L 22 are the lengths of the working medium flow direction on the oil heat dissipation side, the cold side, the water heat dissipation side and the cold side respectively;

[0381] (21) Since the oil and water radiators are arranged in series first and then in parallel with the intercooler, the cooling air resistance Δp on the cold side of the intercooler is 32 Equal to the total resistance of cooling air passing through the oil radiator and water radiator:

[0382] Δp 32 =Δp 12 +Δp 22 (50)

[0383] (22) f factor on the cold side of the intercooler 32 The calculation formula is shown in formula (47), the cold side Reynolds number Re 32 The calculation formula is shown in formula (48), Δp 32The calculation formula is shown in formula (49). Therefore, the combined formula (47)(48)(49) can be used to infer the flow rate u of the cooling air on the cold side of the intercooler: 32 , as shown in formula (50):

[0384] f 32 =1.136(a 32 / D h32 )^(-0.781)*(δ f32 / D h32 )^(0.534)*Re 32 ^(-0.198)(51)

[0385]

[0386]

[0387]

[0388] Among them, ρ 32 is the density of cooling air on the cold side of the intercooler; μ 32 is the dynamic viscosity of the cooling air on the cold side of the intercooler; D h32 , L 32 、a 32 and δ 32 They are the hydraulic diameter of the cold side fin of the intercooler, the cold side working medium flow length, the fin height and the fin thickness;

[0389] (23) According to the structural parameters of the intercooler and the obtained cooling air velocity on the cold side, calculate the cooling air volume m on the cold side of the intercooler 3 , kg / s:

[0390] m 3 =ρ 32 u 32 F 3c (55)

[0391] (24) Based on the assumed cooling air volume on the cold side of the oil radiator and water radiator, combined with the cooling air volume on the cold side of the intercooler obtained by reverse calculation, the total cooling air volume m passing through the power system heat dissipation assembly is calculated. a ; Input the resistance data Δp of cooling air passing through the power system's power compartment and grille other , calculate the total cooling wind resistance Δp through the power system heat dissipation assembly a :

[0392] m a =m 12 +m 3 (56)

[0393] Δp a =Δp12 +Δp 22 +Δp other =Δp 32 +Δp other (57)

[0394] Among them, Δp 32 Indicates the cooling wind resistance on the cold side of the intercooler, Δp 12 Indicates the cooling wind resistance on the cooling side of the oil radiator, Δp 22 Indicates the cooling wind resistance on the water radiator cooling side, m 12 Indicates the cooling air volume through the oil radiator and water radiator, m 3 Indicates the cooling air volume passing through the intercooler;

[0395] (25) The cooling air is sucked into the power system heat dissipation assembly by the fan, and the static pressure and air volume need to satisfy the characteristic curve of the fan. Assuming that there are x fans, it is determined whether the total cooling air volume / x calculated by the oil radiator and water radiator air volumes assumed in step (2) and the total cooling air resistance satisfy the characteristic curve. If so, the assumption in step (2) is correct and the calculation continues. Otherwise, the cooling air volume through the oil radiator and water radiator in step (2) is re-assumed;

[0396] (26) Assume that the heat dissipation of the intercooler is Q 3j ;

[0397] (27) Calculate the cooling air outlet temperature T on the cold side of the intercooler 32 ℃:

[0398]

[0399] Among them, c 3a is the specific heat capacity of the cooling air on the cold side of the intercooler, kJ·kg -1 ·K -1 ;

[0400] (28) The qualitative temperature of each working fluid is calculated based on the inlet and outlet temperatures of the cold and hot sides of the intercooler. The qualitative temperature of the hot side of the intercooler is T 31 , intercooler cold side cooling air qualitative temperature T 32 :

[0401]

[0402]

[0403] (29) According to the inlet and outlet temperatures of the intercooler, calculate the P of the intercooler 3 , R 3 Value, check the PR diagram to get the temperature difference correction coefficient n 3 :

[0404]

[0405]

[0406] (30) According to the temperature difference correction coefficient n 3 , calculate the temperature difference ΔT between the cold and hot sides of the intercooler 3 ,℃:

[0407]

[0408] (31) According to the qualitative temperature of each working fluid on the cold and hot sides of the intercooler, the physical parameters of each working fluid are determined, and the working fluid flow rate u on the hot and cold sides of the intercooler is calculated respectively. 31 、u 32 , kg / s:

[0409]

[0410]

[0411] Among them, ρ q , 32 They are the density of the air on the hot side of the intercooler and the density of the cooling air on the cold side of the intercooler, kg / m 3

[0412] (32) According to the qualitative temperature of each working fluid on the cold and hot sides of the intercooler, the physical parameters of each working fluid are determined, and combined with the obtained working fluid flow rate, the working fluid flow Reynolds number Re on the hot and cold sides of the intercooler is calculated respectively. 31 、Re 32 :

[0413]

[0414]

[0415] Among them, μ 31 , μ 32 They are the dynamic viscosity of the air on the hot side of the intercooler and the dynamic viscosity of the cooling air on the cold side of the intercooler, Pa·s;

[0416] (33) According to the structural dimension parameters of the fins on the cold and hot sides of the intercooler, combined with the calculated Reynolds number, the j factor j on the hot and cold sides is calculated respectively. 31 、j 32 , and the factor f 31 、f 32 This patent takes the intercooler with serrated fins on the cold side and straight fins on the hot side as an example:

[0417] j 31 =0.242(a 31 / D h31 )^(-0.322)*(δ31 / D h31 )^(0.089)*Re 31 ^(-0.368)(68)

[0418]

[0419] f 31 =1.136(a 31 / D h31 )^(-0.781)*(δ 31 / D h31 )^(0.534)*Re 31 ^(-0.198) (70)

[0420]

[0421] Among them, a 31 is the fin height on the hot side of the intercooler, mm; δ 31 is the fin thickness on the hot side of the intercooler, mm;

[0422] (34) According to the flow rate of the working fluid on the cold and hot sides of the intercooler and the free flow area of ​​each channel, the working fluid mass flow rate G on the hot and cold sides of the intercooler is calculated respectively. 31 , G 32 ,kg / m 2 :

[0423]

[0424]

[0425] (35) According to the physical parameters of the working fluid on the cold and hot sides of the intercooler, combined with the calculated j factor and mass flow rate, the heat transfer coefficient α of the hot and cold sides of the intercooler is calculated respectively. 31 , α 32 , kJ·m -2 ·K -1 :

[0426]

[0427]

[0428] where c p31 、c p32 They are the constant pressure specific heat capacity of the working fluid on the hot side of the intercooler and the constant pressure specific heat capacity of the working fluid on the cold side of the intercooler, kJ·kg -1 ·K -1 ; Pr 31 , Pr 32 They are the Prandtl number of the working fluid on the hot side of the intercooler and the Prandtl number of the working fluid on the cold side of the intercooler respectively;

[0429] (36) According to the heat transfer coefficient and structural parameters of the cold and hot sides of the intercooler, the fin efficiency η of the hot and cold sides of the intercooler is calculated respectively. f31 , η f32 :

[0430]

[0431]

[0432] Among them, H 31 , H 32 are the wing heights of the hot and cold sides of the intercooler, mm; P 31 , P 32 are the fin cross-section circumferences of the hot and cold sides of the intercooler, mm; λ 31 , 32 are the thermal conductivity of the fins on the hot and cold sides of the intercooler, W·m -1 ·K -1 ; S 31 , S 32 Respectively, the cross-sectional area of ​​the fins on the hot side and the cold side of the intercooler, mm 2 ;

[0433] (37) According to the heat transfer coefficient and structural parameters of the cold and hot sides of the intercooler, combined with the calculated temperature difference between the cold and hot sides, the heat dissipation Q of the intercooler is calculated. 3s , compare the intercooler heat dissipation Q assumed in step (26) 3j The calculated Q 3s , if |Q 3s -Q 3j |<0.01kW, then step (26) is assumed to be correct, Q 3s This is the calculation result of the heat dissipation capacity of the intercooler. On the contrary, re-assume:

[0434]

[0435] (38) According to the calculation results of the f factor on the hot side of the intercooler, combined with the structural parameters and physical parameters of the hot side of the intercooler, the flow resistance Δp of the working fluid on the hot side of the intercooler is calculated. 31 :

[0436]

[0437] Among them, L 31 is the length of the hot side of the intercooler in the direction of working medium flow;

[0438] (39) If (18), (19), (25), and (37) are all verified to be true, the final iterative calculation result of the heat balance calculation of the heat dissipation assembly is obtained, including the heat dissipation of the oil radiator, water radiator, and intercooler, the cooling air flow rate, the cold side and hot side resistance of each radiator, and other data.

[0439] Calculation example:

[0440] Input the core size, fin type, fin size and other structural parameters of the heat dissipation assembly oil radiator, water radiator and intercooler, calculate the heat exchange area, free flow area, fin efficiency, hydraulic diameter and other parameters of the cold and hot sides of each radiator; connect the oil radiator and water radiator in series, and then connect them in series with the intercooler, and input the known parameters of each radiator. As shown in Table 1:

[0441] Table 1 Calculation structure parameter input

[0442]

[0443]

[0444] Three fans are used to introduce cooling air. The characteristic equation of the fan at a certain speed is Δp = e 7.28675 +0.5048m-0.05855m , the remaining pressure drop of the power cabin and the grille is 2500Pa. Through the calculation process of the present invention, after iterative calculation, the calculation results are shown in Table 2:

[0445] Table 2 Calculation results

[0446] Oil water dispersion Intercooler Hot side air volume kg / s 1.6887 9.8867 0.6964 Cold side air volume kg / s 10.3300 10.3300 4.7744 Cold side pressure drop Pa 368.8916 810.6010 1179.4925 Hot side inlet temperature ℃ 120 103 230 Hot side outlet temperature ℃ 83.55 96.24 80 Cold side inlet temperature ℃ 55 65.10 55 Cold side outlet temperature ℃ 65.10 88.13 81.21 Heat dissipation capacity kW 125.4366 203.6628 122.9658

Claims

1. Series-parallel type heat dissipation assembly structure, characterized in that: It comprises an oil radiator (1), a water radiator (2) and an intercooler (3); the water radiator (2) is arranged at the bottom of the oil radiator (1), and the intercooler (3) is arranged at the other end of the water radiator (2).

2. A method for calculating the thermal balance of a series-parallel type heat dissipation assembly, characterized in that: The following steps are involved: Step S1: input the core size, fin type, and fin size and structure parameters of each radiator in the heat dissipation assembly, where the subscripts c and h represent the low temperature side and the high temperature side of the radiator, respectively; Step S2: Input the known parameters of the oil flowing through each radiator: oil cooling side oil flow m o , Water pump flow rate on water cooling side m w , Intercooler hot side intake volume m q , Oil inlet temperature T on the oil cooling side 11 ', water inlet temperature T on the water cooling side 21 '、Intercooler hot side inlet temperature T 31 ', intercooler hot side outlet temperature T 31 ″、Inlet temperature of cooling air T a ; Step S3: Assume that the cooling air volume m passing through the oil radiator and the water radiator side 12 , Assume that the heat dissipation of the oil radiator is Q 1j , Assume that the heat dissipation of the water radiator is Q 2j , calculate the oil outlet temperature T on the oil cooling side 11 ″、Oil radiator cooling air outlet temperature T 12 ″: Among them, c o 、c 12 are the specific heat capacities of the engine oil and the cooling air on the cooling side of the oil radiator; Step S4: Water outlet temperature T at the water cooling side 21 ″、Inlet temperature of cooling air on the cooling side of the water radiator T 22 '、Inlet temperature of cooling air on the cooling side of the water radiator T 22 ″: T 22 ′=T 12 ″ Among them, c w 、c 22 are the specific heat capacities of water and cooling air respectively; Step S5: Calculate the qualitative temperature of each working fluid based on the inlet and outlet temperatures of the oil radiator and the water radiator on the cold side and the hot side. The qualitative temperature is used to determine the physical parameters of each working fluid. The qualitative temperature of the oil on the oil radiator side is T 11 , Cooling air qualitative temperature T on the cooling side of the oil radiator 12 , water qualitative temperature T on the water cooling side 21 , Qualitative temperature of cooling air on the cooling side of water radiator T 22 : Step S6: Calculate the P1 and R1 values ​​of the oil radiator according to the inlet and outlet temperatures of the oil radiator, and obtain the temperature difference correction coefficient n1 by looking up the PR diagram; calculate the P2 and R2 values ​​of the water radiator according to the inlet and outlet temperatures of the water radiator, and obtain the temperature difference correction coefficient n2 by looking up the PR diagram: Where, T' 21 Indicates the inlet temperature of the water cooling side; T' 12 Indicates the inlet temperature of the oil radiator on the cold side; T” 12 Indicates the outlet temperature of the oil radiator on the cold side; T” 21 Indicates the outlet temperature of the water cooling side; T” 11 Indicates the outlet temperature of the oil heat dissipation side; T' 11 Indicates the inlet temperature of the oil heat dissipation side; Step S7: Calculate the temperature differences ΔT1 and ΔT2 on the cold and hot sides of the oil radiator and water radiator respectively according to the temperature difference correction coefficients n1 and n2 found, and use the average logarithmic temperature difference formula for calculation: Step S8: According to the qualitative temperature of each working medium on the cold and hot sides of the oil radiator and the water radiator, determine the physical parameters of each working medium, and calculate the working medium flow rate u on the oil heat dissipation side and the cold side respectively. 11 、u 12 , calculate the working fluid flow rate u on the water cooling side and the cold side respectively 21 、u 22 : Among them, ρ o , 12 , w and ρ 22 They are the density of the oil on the oil heat dissipation side, the density of the cooling air on the oil heat dissipation side, the density of the water on the water heat dissipation side, and the density of the cooling air on the water heat dissipation side; Step S9: According to the qualitative temperature of each working fluid on the cold and hot sides of the oil radiator and the water radiator, determine the physical parameters of each working fluid, and calculate the working fluid flow Reynolds number Re on the oil heat dissipation side and the cold side respectively in combination with the obtained working fluid flow rate 11 、Re 12 , calculate the Reynolds number Re of the working fluid flow on the water cooling side and the cold side respectively 21 、Re 22 : Among them, D h11 , D h12 , D h21 and D h22 are the hydraulic diameter of the fin on the oil heat dissipation side, the hydraulic diameter of the fin on the oil heat dissipation cooling side, the hydraulic diameter of the fin on the water heat dissipation side, and the hydraulic diameter of the fin on the water heat dissipation cooling side; μ 11 , μ 12 , μ 21 and μ 22 They are the dynamic viscosity of the oil on the oil heat dissipation side, the dynamic viscosity of the cooling air on the oil heat dissipation side, the dynamic viscosity of the water on the water heat dissipation side, and the dynamic viscosity of the cooling air on the water heat dissipation side; Step S10: Calculate the j factor j of the hot side and the cold side respectively according to the structural dimension parameters of each fin on the cold side and the hot side of the oil radiator and the calculated Reynolds number. 11 、j 12 , and the factor f 11 、f 12 : j 11 S 0.242(a 11 / D h11 )^(-0.322)*(δ f11 / D h11 )^(0.089)*Re 11 ^(-0.368) j 12 S 0.242(a 12 / D h12 )^(-0.322)*(δ f12 / D h12 )^(0.089)*Re 12 ^(-0.368) f 11 1.136(a 11 / D h11 )^(-0.781)*(δ f11 / D h11 )^(0.534)*Re 11 ^(-0.198) f 12 1.136(a 12 / D h12 )^(-0.781)*(δ f12 / D h12 )^(0.534)*Re 12 ^(-0.198) Among them, a 11 、a 12 are the fin heights on the oil cooling side and the cold side respectively; δ 11 ,δ 12 are the fin thicknesses on the oil cooling side and the cold side, respectively; Step S11: Calculate the heat transfer factor j of the hot side and the cold side respectively according to the structural dimension parameters of each fin on the cold and hot sides of the radiator and the calculated Reynolds number. 21 、j 22 , and the friction factor f 21 、f 22 : j 21 S 0.242(a 21 / D h21 )^(-0.322)*(δ 21 / D h21 )^(0.089)*Re 21 ^(-0.368) j 22 S 0.242(a 22 / D h22 )^(-0.322)*(δ 22 / D h22 )^(0.089)*Re 22 ^(-0.368) f 21 1.136(a 21 / D h21 )^(-0.781)*(δ 21 / D h21 )^(0.534)*Re 21 ^(-0.198) f 22 1.136(a 22 / D h22 )^(-0.781)*(δ 22 / D h22 )^(0.534)*Re 22 ^(-0.198) Among them, a 21 、a 22 are the fin heights on the water cooling side and the cooling side respectively; δ 21 ,δ 22 are the fin thicknesses on the water cooling and cooling sides, respectively; Step S12: Calculate the mass flow rate G of the working medium on the oil heat dissipation side and the cold side respectively according to the flow rate of the working medium on the cold and hot sides of the oil radiator and the water radiator and the free flow area of ​​each channel. 11 , G 12 , calculate the working fluid mass flow rate G on the water cooling side and the cold side respectively 21 , G 22 : Among them, m 12 Indicates the cooling air volume through the oil radiator and water radiator, m w represents the water pump flow rate on the water cooling side, m0 represents the oil flow rate on the oil cooling side, F 1h Indicates the free flow area on the oil cooling side, F 1C Indicates the free flow area on the cold side of the oil radiator, F 2h Indicates the free flow area on the water cooling side, F 2C Indicates the free flow area on the cold side of the water radiator; Step S13: Calculate the heat transfer coefficient α of the oil heat dissipation side and the cold side respectively according to the physical parameters of the working fluids on the cold and hot sides of the oil radiator and the water radiator, combined with the calculated j factor and mass flow rate 11 , α 12 , calculate the heat transfer coefficient α of the water cooling side and the cold side respectively 21 , α 22 : Among them, c p11 、c p12 、c p21 and c p22 They are the constant pressure specific heat capacity of the working fluid on the oil heat dissipation side, the constant pressure specific heat capacity of the working fluid on the oil heat dissipation cooling side, the constant pressure specific heat capacity of the working fluid on the water heat dissipation cooling side, and the constant pressure specific heat capacity of the working fluid on the water heat dissipation cooling side; Pr 11 , Pr 12 , Pr 21 and Pr 22 They are the Prandtl number of the working fluid on the oil heat dissipation side, the Prandtl number of the working fluid on the oil heat dissipation side, the Prandtl number of the working fluid on the water heat dissipation side, and the Prandtl number of the working fluid on the water heat dissipation side; Step S14: Calculate the fin efficiency η of the oil heat dissipation side and the cold side according to the heat transfer coefficients and structural parameters of the cold and hot sides of the oil radiator and water radiator, respectively. f11 , η f12 ; Calculate the fin efficiency η on the water cooling side and the cooling side respectively f21 , η f22 : Among them, H 11 , H 12 , H 21 and H 22 are the wing heights of the oil cooling side, the cold side and the water cooling side, the cold side; P 11 , P 12 , P 21 and P 22 are the fin cross-section perimeters of the oil cooling side, the cold side and the water cooling side, the cold side; λ 11 , 12 , 21 and λ 22 are the thermal conductivity of the fins on the oil cooling side, the cold side and the water cooling side, the cold side; S 11 , S 12 , S 21 and S 22 are the cross-sectional areas of the fins on the oil cooling side, the cold side and the water cooling side, the cold side; Step S15: Calculate the heat dissipation Q of the oil radiator based on the heat transfer coefficients and structural parameters of the cold and hot sides of the oil radiator, combined with the calculated temperature difference between the cold and hot sides and the fin efficiency. 1s , compare the oil heat dissipation Q assumed in step S3 1j The calculated Q 1s , if |Q 1s -Q 1j |<0.01kW, then step S3 is assumed to be correct, Q 1s This is the calculation result of the heat dissipation capacity of the oil radiator. Conversely, re-assume: Step S16: Calculate the heat dissipation Q of the water radiator based on the heat transfer coefficients and structural parameters of the cold and hot sides of the water radiator, combined with the calculated temperature difference between the cold and hot sides and the fin efficiency. 2s , compare the water heat dissipation Q assumed in step S3 2j The calculated Q 2s , if |Q 2s -Q 2j |<0.01kW, then step S3 is assumed to be correct, Q 2s This is the calculation result of the heat dissipation capacity of the water radiator. Conversely, re-assume: Step S17: Based on the calculation results of the f factors of the cold and hot sides of the oil radiator and the water radiator, combined with the structural parameters and physical parameters of the cold and hot sides of the oil radiator and the water radiator, the working medium flow resistance Δp of the hot side and the cold side of the oil radiator is calculated respectively. 11 , Δp 12 , calculate the working fluid flow resistance Δp on the hot side and cold side of the water radiator respectively 21 , Δp 22 Among them, L 11 , L 12 , L 21 and L 22 are the lengths of the working medium flow direction on the oil heat dissipation side, the cold side, the water heat dissipation side and the cold side respectively; Step S18: Since the oil radiator and the water radiator are first arranged in series and then connected in parallel with the intercooler, the cooling wind resistance Δp on the cold side of the intercooler 32 Equal to the total resistance of cooling air passing through the oil radiator and water radiator: Δp 32 =Δp 12 +Δp 22 Step S19: Based on the f factor f on the cold side of the intercooler 32 , cold side Reynolds number Re 32 , Cooling wind resistance Δp 32 , the cooling air velocity u on the cold side of the intercooler can be inferred 32 : f 32 1.136(a 32 / D h32 )^(-0.781)*(δ f32 / D h32 )^(0.534)*Re 32 ^(-0.198) Among them, ρ 32 is the density of cooling air on the cold side of the intercooler; μ 32 is the dynamic viscosity of the cooling air on the cold side of the intercooler; D h32 , L 32 、a 32 and δ 32 They are the hydraulic diameter of the intercooler cold side fin, the cold side working medium flow length, the fin height and the fin thickness; Step S20: Calculate the cooling air volume m3 on the cold side of the intercooler based on the structural parameters of the intercooler and the obtained cooling air velocity on the cold side: m3=ρ 32 u 32 F 3c Among them, ρ 32 is the density of cooling air on the cold side of the intercooler; μ 32 is the dynamic viscosity of the cooling air on the cold side of the intercooler, F 3c It represents the free flow area on the cold side of the intercooler; Step S21: Calculate the total cooling air volume m passing through the power system heat dissipation assembly based on the assumed cooling air volume of the oil radiator and water radiator on the cold side and the intercooler on the cold side calculated by reverse calculation. a ; Input the resistance data Δp of cooling air passing through the power system's power compartment and grille other , calculate the total cooling wind resistance Δp through the power system cooling assembly a : m a =m 12 +m3 Δp a =Δp 12 +Δp 22 +Δp other =Δp 32 +Δp other Among them, Δp 32 Indicates the cooling wind resistance on the cold side of the intercooler, Δp 12 Indicates the cooling wind resistance on the cooling side of the oil radiator, Δp 22 Indicates the cooling wind resistance on the water radiator cooling side, m 12 It indicates the cooling air volume through the oil radiator and water radiator, and m3 indicates the cooling air volume through the intercooler; Step S22: The cooling air is sucked into the power system heat dissipation assembly by the fan, and the static pressure and air volume need to satisfy the characteristic curve of the fan. Assuming that there are x fans, it is determined whether the total cooling air volume / x calculated by the air volume of the oil radiator and the water radiator assumed in step S3 and the total cooling air resistance satisfy the characteristic curve. If so, the assumption in step S3 is correct and the calculation continues. Otherwise, the cooling air volume through the oil radiator and the water radiator in step S3 is re-assumed. Step S23: Assume that the heat dissipation of the intercooler is Q 3j , calculate the cooling air outlet temperature T on the cold side of the intercooler 32 ″: Among them, T a Indicates the inlet temperature of cooling air; Q 3j Indicates the heat dissipation of the intercooler; C 3a represents the specific heat capacity of the cooling air on the cold side of the intercooler; m3 represents the cooling air volume on the cold side of the intercooler; Step S24: Calculate the qualitative temperature of each working fluid based on the inlet and outlet temperatures of the cold and hot sides of the intercooler. The qualitative temperature of the hot side of the intercooler is T 31 , intercooler cold side cooling air qualitative temperature T 32 : Step S25: Calculate the P3 and R3 values ​​of the intercooler according to the inlet and outlet temperatures of the intercooler, and obtain the temperature difference correction coefficient n3 by looking up the PR diagram: Among them, T 32 ″Intercooler cold side cooling air outlet temperature, T 31 ′ represents the intercooler hot side inlet temperature, T 31 ″ represents the intercooler hot side outlet temperature, T' 32 Indicates the cooling air inlet temperature on the cold side of the intercooler; Step S26: Calculate the temperature difference ΔT3 between the cold and hot sides of the intercooler according to the found temperature difference correction coefficient n3: Step S27: According to the qualitative temperature of each working fluid on the cold and hot sides of the intercooler, determine the physical parameters of each working fluid, and calculate the working fluid flow rate u on the hot and cold sides of the intercooler respectively. 31 、u 32 : Among them, ρ q , 32 They are the density of the air on the hot side of the intercooler and the density of the cooling air on the cold side of the intercooler; Step S28: According to the qualitative temperature of each working fluid on the cold and hot sides of the intercooler, determine the physical parameters of each working fluid, and calculate the working fluid flow Reynolds number Re on the hot and cold sides of the intercooler respectively in combination with the obtained working fluid flow rate. 31 、Re 32 : Among them, μ 31 , μ 32 They are the dynamic viscosity of the air on the hot side of the intercooler and the dynamic viscosity of the cooling air on the cold side of the intercooler; Step S29: Calculate the j factor j for the hot side and the cold side 31 、j 32 , and the factor f 31 、f 32 : j 31 S 0.242(a 31 / D h31 )^(-0.322)*(δ 31 / D h31 )^(0.089)*Re 31 ^(-0.368) f 31 1.136(a 31 / D h31 )^(-0.781)*(δ 31 / D h31 )^(0.534)*Re 31 ^(-0.198) Among them, a 31 is the fin height on the hot side of the intercooler; δ 31 is the thickness of the fins on the hot side of the intercooler; Step S30: Calculate the working medium mass flow rate G on the hot side and the cold side of the intercooler according to the flow rate of the working medium on the cold and hot sides of the intercooler and the free flow area of ​​each channel. 31 , G 32 : Where m3 represents the cooling air volume on the cold side of the intercooler, m q Indicates the air intake volume on the hot side of the intercooler, F 3h It represents the free flow area on the hot side of the intercooler; Step S31: Calculate the heat transfer coefficient α of the hot side and the cold side of the intercooler according to the physical parameters of the working fluid on the cold and hot sides of the intercooler, combined with the calculated j factor and mass flow rate. 31 , α 32 : Among them, c p31 、c p32 They are the constant pressure specific heat capacity of the working fluid on the hot side of the intercooler and the constant pressure specific heat capacity of the working fluid on the cold side of the intercooler; Pr 31 , Pr 32 They are the Prandtl number of the working fluid on the hot side of the intercooler and the Prandtl number of the working fluid on the cold side of the intercooler respectively; Step S32: Calculate the fin efficiency η of the hot side and the cold side of the intercooler according to the heat transfer coefficient and structural parameters of the cold and hot sides of the intercooler f31 , η f32 : Among them, H 31 , H 32 are the wing heights of the hot and cold sides of the intercooler; P 31 , P 32 are the fin cross-section perimeters of the hot and cold sides of the intercooler; 31 , 32 are the thermal conductivity of the fins on the hot and cold sides of the intercooler; S 31 , S 32 are the cross-sectional areas of the fins on the hot and cold sides of the intercooler, respectively; Step S33: Calculate the heat dissipation Q of the intercooler based on the heat transfer coefficients and structural parameters of the cold and hot sides of the intercooler and the calculated temperature difference between the cold and hot sides. 3s , compare the intercooler heat dissipation Q assumed in step S23 3j The calculated Q 3s , if |Q 3s -Q 3j |<0.01kW, then step S23 assumes that it is correct, Q 3s This is the calculation result of the heat dissipation capacity of the intercooler. On the contrary, re-assume: Among them, α 31 Indicates the heat transfer coefficient of the hot side of the intercooler; A 3h represents the heat exchange area on the hot side of the intercooler, α 32 Indicates the heat transfer coefficient of the cold side of the intercooler; A 3c Indicates the heat exchange area on the cold side of the intercooler; ΔT3 indicates the temperature difference between the cold and hot sides of the intercooler; Step S33: Calculate the working fluid flow resistance Δp on the hot side of the intercooler based on the calculation result of the f factor on the hot side of the intercooler and the structural parameters and physical parameters of the hot side of the intercooler. 31 : Among them, L 31 is the length of the hot side of the intercooler in the direction of working fluid flow, D h31 represents the hydraulic diameter of the hot side fin of the intercooler, ρ q Indicates the density of the air on the hot side of the intercooler, μ 31 Indicates the dynamic viscosity of the air on the hot side of the intercooler; Step S34: Repeat the iteration of step S3 and step S23, verify step S15, step S16, step 22, and step S33, and obtain the final calculation results of the thermal balance parameters of the heat dissipation assembly, including the heat dissipation of the oil radiator, water radiator and intercooler, the cooling air flow rate, and the cold side and hot side resistance data of each radiator.

3. A method for calculating heat balance of a series-parallel heat dissipation assembly according to claim 2, characterized in that: The common heat dissipation assembly includes an intercooler, an oil radiator, a water radiator and a fan. The oil radiator and the water radiator are connected in series and in parallel with the intercooler.

4. A method for calculating heat balance of a series-parallel heat dissipation assembly according to claim 2, characterized in that: The oil radiator is referred to as the oil radiator, and the water radiator is referred to as the water radiator.

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