A design method and device for high-temperature gas cooling with equal Mach number

Abstract

The present invention provides a design method and device for high-temperature gas cooling with equal Mach number, including: establishing a cooling device model, including a housing model and a heat exchange structure model; importing given design conditions into a data analysis unit, in which a data analysis criterion is set: the proportion of the solid area of the heat exchange structure model in the front and rear adjacent cross-sections perpendicular to the high-temperature gas flow direction in the cooling device model is the same as that of the intercepted cross-sectional area; analyzing according to the data analysis criterion in combination with the design conditions to obtain the cross-sectional areas of the air inlet and outlet of the heat exchange structure model and the cross-sectional areas of the air inlet and outlet of the cooling device model; and then determining the size of the cooling device model and the size of the heat exchange structure model. The present invention solves the problems that when the flight altitude is relatively high and the Mach number is relatively fast, the compressor of the aerospace engine cannot effectively compress the high-temperature incoming flow, so that the engine is difficult to operate at a higher Mach number and the problem of recycling of high-temperature exhaust gas.

Description

[0001] Field of the Invention

[0002] The present invention belongs to the technical field of air-breathing aerospace engine equipment, and particularly relates to a design method and device for cooling high-temperature gas at constant Mach number. Background Art

[0003] The air-breathing aerospace engine is an ideal power component for near-earth aircraft. Common air-breathing aerospace engines include turbojet, ramjet, and their combined engines. Their common working process includes necessary compression of the incoming air, and further heating of the pressurized air flow (such as by chemical combustion heating method). After the gas obtains sufficient energy, it expands to do work and generate thrust. When such engines need to operate at higher altitudes and faster flight Mach numbers (especially above an altitude of 20 km and a speed of Mach 3 or more), the total temperature of the incoming air captured by the inlet is already quite high (see Table 1 - Typical flight states of air-breathing aerospace engines and their corresponding total temperatures of the incoming air):

[0004] Table 1 Typical flight states of air-breathing aerospace engines and their corresponding total temperatures of the incoming air

[0005] Height H Mach number Total temperature T (km) (K) 6.0 1.60 377.1 10.0 1.85 376.0 11.0 2.00 390.4 12.0 2.10 408.2 13.0 2.12 410.9 14.0 2.15 417.3 15.0 2.20 426.3 16.0 2.30 446.0 17.0 2.50 487.5 18.0 2.60 509.5 19.0 2.80 556.2 20.0 3.00 607.7 22.0 3.50 754.5 23.0 3.70 822.3 24.0 4.00 930.8 25.0 4.29 1036.8 26.0 4.65 1179.9 27.0 5.00 1331.9 28.0 5.40 1547.6

[0006] At this time, if the incoming air is not cooled necessarily, the common materials of the compression components will fail to withstand the higher temperature after gas pressurization at a flight Mach number above 3.0 (see Table 2 - Comparison of total temperatures before and after 5-fold pressurization of incoming air at different speeds), resulting in the entire engine being unable to operate normally.

[0007] Table 2 Comparison of total temperatures before and after 5-fold pressurization of incoming air at different speeds

[0008] Mach number Total temperature T Pressure ratio Total temperature after pressurization (K) (K) 2.50 487.5 5 772.1 2.60 509.5 5 807.0 2.80 556.2 5 880.9 3.00 607.7 5 962.5 3.50 754.5 5 1195.0 3.70 822.3 5 1302.4 4.00 930.8 5 1474.2 4.29 1036.8 5 1642.1 4.65 1179.9 5 1868.7 5.00 1331.9 5 2109.5 5.40 1547.6 5 2451.2

[0009] Therefore, in order to effectively expand the working upper limit of the turbocharged air-breathing engine, pre-cooling the incoming air at a higher Mach number (such as above Mach 3.0) to reduce its total temperature so that the total temperature of the air flow after pressurization can still be maintained within the working temperature range of the compressor material is an effective technical path.

[0010] In addition, the turbine component of the air-breathing aerospace engine plays a role in driving the compressor. The waste gas of the turbine after doing work often still has a relatively high remaining temperature. If it is directly discharged into the atmosphere, some energy will not be fully utilized, reducing the overall efficiency of the engine. Summary of the Invention

[0011] The present invention provides a design method and device for high-temperature gas cooling with equal Mach number, which solves the problems that when the flight altitude is relatively high and the Mach number is relatively fast (especially at an altitude of 20 km and a speed above Mach 3), the compressor of the aerospace engine cannot effectively compress the high-temperature incoming flow, thus making it difficult for the engine to operate at a higher Mach number and the problem of recycling high-temperature exhaust gas.

[0012] A design method for high-temperature gas cooling with equal Mach number, the method steps include:

[0013] Step 100: Establish a cooling device model, including a housing model and a heat exchange structure model fixed inside the housing model. The inside of the heat exchange structure model is passed through by a coolant, and the gap between the heat exchange structure model and the housing model is an air passage through which high-temperature gas passes;

[0014] Step 200: Import the given design conditions into the data analysis unit. The design conditions include the Mach number of the high-temperature gas flow velocity at the inlet and outlet of the cooling device model, the air pressure and temperature at the inlet and outlet of the heat exchange structure model, and the Mach number of the high-temperature gas flow velocity in the air passage between the inlet and outlet of the heat exchange structure model, that is, inside the heat exchange structure model;

[0015] In the data analysis unit of Step 300, a data analysis criterion is set: the ratio of the solid area of the heat exchange structure model in the front and rear adjacent cross-sections perpendicular to the high-temperature gas flow direction in the cooling device model to the area of the intercepted cross-section is the same, and the solid area is the cross-sectional area of the heat exchange structure model; based on the design conditions, the cross-sectional areas of the inlet and outlet of the heat exchange structure model and the cross-sectional areas of the inlet and outlet of the cooling device model in the cross-section perpendicular to the high-temperature gas flow direction are analyzed according to the data analysis criterion;

[0016] Step 400: Determine the size of the cooling device model and the size of the heat exchange structure model according to the cross-sectional areas of the inlet and outlet of the heat exchange structure model and the cross-sectional areas of the inlet and outlet of the cooling device model.

[0017] In some embodiments of the present application, the Mach number of the high-temperature gas flow velocity in the heat exchange structure model in Step 200 is the same in segments or the same throughout from the inlet of the heat exchange structure model to the outlet of the heat exchange structure.

[0018] In some embodiments of the present application, the data analysis criterion in Step 300 is specifically: at any cross-section inside the cooling device model perpendicular to the high-temperature gas flow direction, the ratio of the solid area of the heat exchange structure model to the total cross-sectional area is the same as the ratio of the solid area at the inlet and outlet cross-sections of the heat exchange structure model.

[0019] In some embodiments of the present application, the Mach number of the high-temperature gas flow velocity at any cross-section perpendicular to the high-temperature gas flow direction within the heat exchange structure model is the same.

[0020] In some embodiments of the present application, according to the Mach number of the high-temperature gas flow velocity within the given heat exchange structure model, based on the basic theory of aerodynamics and the physical properties of the high-temperature gas, the proportion value of the solid area of the heat exchange structure model at any cross-section perpendicular to the high-temperature gas flow direction in the cooling device model can be calculated.

[0021] In some embodiments of the present application, the analysis process within the data analysis unit is as follows:

[0022] Step 301: Analyze and obtain the cross-sectional areas at the inlet and outlet of the heat exchange structure model according to the design conditions.

[0023] Step 302: Analyze and obtain the cross-sectional areas at the inlet and outlet of the cooling device model according to the design conditions.

[0024] Step 303: Based on the results of Step 301 and Step 302, obtain the proportion of the solid area of the heat exchange structure model at the cross-section perpendicular to the high-temperature gas flow direction at the inlet and outlet of the heat exchange structure model.

[0025] In some embodiments of the present application, the heat exchange structure model selects one of a tube bundle structure, a cross-flow structure, or a plate structure, and the length of the heat exchange structure model is less than the length of the cooling device model.

[0026] In the second aspect of the present invention, there is provided an isentropic Mach number high-temperature gas cooling device designed based on the isentropic Mach number high-temperature gas cooling design method, including

[0027] a heat exchanger housing and a heat exchange structure. The heat exchange structure is fixed within the heat exchanger housing, and the gap with the interior of the heat exchanger housing forms an air passage. A coolant flows through the heat exchange structure to lower the temperature.

[0028] At any cross-section perpendicular to the high-temperature gas flow direction within the heat exchanger housing, the proportion of the solid area of the heat exchange structure in the total cross-sectional area is the same as the proportion of the solid area at the inlet and outlet cross-sections of the heat exchange structure.

[0029] In some embodiments of the present application, the heat exchange structure includes a plurality of coolant channels through which a coolant flows and a plurality of heat dissipation fins. The coolant channels are fixed within the heat exchanger housing through the heat dissipation fins. An air passage is formed by connecting each coolant channel to other coolant channels and the heat exchanger housing through the heat dissipation fins. At any cross-section perpendicular to the high-temperature gas flow direction, the cross-sectional areas of the heat dissipation fins and the coolant channels are solid areas.

[0030] In some embodiments of the present application, the heat exchanger housing is an irregular-shaped housing or a regular-shaped housing.

[0031] In some embodiments of the present application, the heat exchange structure is selected from one of a tube bundle structure, a cross-flow structure, or a plate structure.

[0032] In some embodiments of the present application, the length of the heat exchange structure is less than the length of the heat exchanger housing.

[0033] The present invention has beneficial effects compared with the prior art:

[0034] 1. The equal Mach number high-temperature gas cooling design method provided by the present invention can accurately determine the weight per unit length of the cooling device in the preliminary design stage, so as to provide necessary and accurate feedback information for the overall engine and aircraft.

[0035] 2. It can effectively avoid the congestion caused by the gas velocity approaching the speed of sound in the air flow channel, thereby avoiding the trap that the preset flow rate cannot pass when the working condition changes.

[0036] 3. It provides a model applicability criterion for the full flow field CFD by the computational fluid dynamics method. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can be obtained according to the provided drawings.

[0038] Figure 1 is a flowchart of the equal Mach number high-temperature gas cooling design method of the present invention;

[0039] Figure 2 is a schematic structural diagram of the cooling device in Embodiment 1 of the present invention;

[0040] Figure 3 In the present invention Figure 2 side view.

[0041] The reference numerals in the figure are:

[0042] 1 - coolant inlet, 2 - coolant outlet, 3 - air inlet, 4 - air outlet; 5 - heat dissipation fins, 6 - coolant channel, 7 - air channel, 8 - heat exchanger housing. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] A design method for high-temperature gas cooling with equal Mach number

[0045] Step 100: Establish a cooling device model, including a housing model and a heat exchange structure model fixed inside the housing model. The inside of the heat exchange structure model is passed through by a coolant, and the gap between the heat exchange structure model and the housing model is an air passage through which high-temperature gas passes.

[0046] Step 200: Import the given design conditions into the data analysis unit. The design conditions include the Mach numbers of the high-temperature gas flow velocities at the inlet and outlet of the cooling device model, the air pressures and temperatures at the inlet and outlet of the heat exchange structure model, and the Mach numbers of the high-temperature gas flow velocities in the air passage between the inlet and outlet of the heat exchange structure model, that is, inside the heat exchange structure model. The high-temperature gas refers to high-Mach-number incoming air and high-temperature turbine exhaust gas.

[0047] In the data analysis unit, a data analysis criterion is set: the ratio of the solid area of the heat exchange structure model in the front and rear adjacent cross-sections perpendicular to the high-temperature gas flow direction in the cooling device model to the area of the intercepted cross-section is the same. The solid area is the cross-sectional area of the heat exchange structure model. Based on the design conditions and according to the data analysis criterion, analyze and obtain the cross-sectional areas of the inlet and outlet of the heat exchange structure model and the cross-sectional areas of the inlet and outlet of the cooling device model in the cross-section perpendicular to the high-temperature gas flow direction.

[0048] Step 400: Determine the dimensions of the cooling device model and the dimensions of the heat exchange structure model according to the cross-sectional areas of the inlet and outlet of the heat exchange structure model and the cross-sectional areas of the inlet and outlet of the cooling device model.

[0049] The design method for high-temperature gas cooling with equal Mach number provided by the present invention can accurately determine the weight per unit length of the cooling device in the preliminary design stage, so as to provide necessary and accurate feedback information for the overall engine and aircraft. In addition, the cooling device model provided by the present invention can be applicable to conditions with a relatively high flight altitude and a relatively high Mach number (especially at an altitude of 20 km and a speed above Mach 3). The compressor of the aerospace engine can effectively compress the high-temperature incoming flow, enabling the engine to operate normally, and can also cool the high-temperature exhaust gas, which is beneficial to solving the problem of recycling and utilization of high-temperature exhaust gas.

[0050] In the present invention, a cooling working fluid with good heat absorption capacity (such as methane, liquid hydrogen, endothermic hydrocarbon fuel, etc.) is used, and a material with good thermal conductivity and heat resistance (such as copper, superalloy, composite material, etc.) is used as a medium to effectively cool the high-temperature gas. In order to effectively isolate the gas to be cooled from the cooling working fluid and prevent them from mixing with each other, the heat exchange structure model can adopt heat exchange structure models such as tube bundle type, plate type, cross-flow type, etc. Any structure model that meets the condition of the solid area ratio at the cross-section in the above design method can be used as the heat exchange structure model.

[0051] If the specific components of the known high-temperature gas to be cooled are known, its physical properties and flow parameters can be accurately mastered. By ensuring that the ratio of the solid area of the heat exchange structure model in the adjacent front and rear cross-sections perpendicular to the flow direction of the high-temperature gas in the cooling device model to the area of the intercepted cross-section is the same, the Mach number of the flow velocity of the high-temperature gas in the heat exchange structure model (referred to as the flow velocity Mach number) is the same in segments or the same throughout the whole process from the inlet to the outlet of the heat exchange structure. The specific ratio of the solid area of the heat exchange structure model is determined according to the Mach number of the flow velocity of the high-temperature gas in the heat exchange structure model (i.e., the airflow Mach number inside the heat exchange structure).

[0052] Specifically, if a Mach number of the high-temperature gas flow in a heat exchange structure model is given, based on the basic theory of aerodynamics and the physical properties of the high-temperature gas, the ratio value of the solid area of the heat exchange structure at any cross-section perpendicular to the high-temperature gas flow direction in the cooling device model can be calculated. Changing this design Mach number, the ratio value of the solid area ratio will change accordingly. Let the Mach numbers at the inlet and outlet of the heat exchange structure model be Ma1, and the Mach numbers at the inlet and outlet of the cooling device model be Ma2. Then the calculation formula for the solid area ratio of the heat exchange structure model is: under the condition that the air temperatures and pressures at the inlets and outlets of the heat exchange structure and the cooling device are the same, f = 1 - y(Ma2) / y(Ma1), where y(Ma) = 1 / Ma·((1 + 0.2·Ma 2 ) / 1.2) 3 , and the value of f is equal to the ratio of the solid area of the heat exchange structure model.

[0053] In a specific embodiment, the data analysis criterion in step 300 can be understood as: at any cross-section perpendicular to the high-temperature gas flow direction inside the cooling device model, the ratio of the solid area of the heat exchange structure model to the total cross-section area is the same as the ratio of the solid area at the inlet and outlet cross-sections of the heat exchange structure model. That is, the Mach number of the high-temperature gas flow velocity at any cross-section perpendicular to the high-temperature gas flow direction in the heat exchange structure model is the same.

[0054] Furthermore, the analysis process in the data analysis unit is as follows:

[0055] Step 301: According to the analysis of the design conditions, based on the air flow area formula of the air inlet and outlet, by sorting out the density and absolute value of the velocity of the high-temperature gas at the air inlet and outlet of the heat exchange structure model, the cross-sectional area at the air inlet and outlet of the heat exchange structure model can be obtained.

[0056] Step 302: According to the analysis of the design conditions, by sorting out the density and absolute value of the velocity of the high-temperature gas at the air inlet and outlet of the cooling device model, the cross-sectional area at the air inlet and outlet of the cooling device model can be obtained.

[0057] Step 303: According to the results of Step 301 and Step 302, obtain the proportion of the solid area of the heat exchange structure model in the cross-section perpendicular to the high-temperature gas flow direction at the air inlet and outlet of the heat exchange structure model.

[0058] In a specific embodiment, the length of the heat exchange structure model is less than the length of the cooling device model, so that the proportion of the solid area of the heat exchange structure in the cross-section can be determined by comparing the flow velocities at the air inlets and outlets of the heat exchange structure model and the cooling device model. The outer shell model can be selected as regular shapes such as cylindrical and elliptical, or irregular shapes.

[0059] Based on the above high-temperature gas cooling design method with equal Mach number, the present invention designs a cooling device, namely a high-temperature gas cooling device with equal Mach number, including: a heat exchanger outer shell and a heat exchange structure. The heat exchange structure is fixed in the heat exchanger outer shell, and the gap with the inside of the heat exchanger outer shell forms an air channel. A coolant is passed through the heat exchange structure for cooling; at any cross-section perpendicular to the air flow direction in the heat exchanger outer shell, the proportion of the solid area of the heat exchange structure in the total cross-sectional area is the same as the proportion of the solid area at the air inlet and outlet cross-sections of the heat exchange structure.

[0060] In the present invention, it can provide strong constraints for the topological optimization of the cooling device, greatly reducing the design uncertainty.

[0061] In a specific embodiment, the heat exchange structure can be selected as a structure in which a plurality of heat dissipation fins wrap the coolant channels, specifically including a plurality of coolant channels through which the coolant passes and a plurality of heat dissipation fins. The coolant channels are fixed in the heat exchanger outer shell through the heat dissipation fins. Each coolant channel is connected to other coolant channels and the heat exchanger outer shell by heat dissipation fins to form an air channel. At any cross-section perpendicular to the air flow direction, the sum of the wall area of the heat dissipation fins and the cross-sectional area of the coolant channels is the solid area, that is, the area where air cannot flow, including the wall area of the coolant channels.

[0062] In some possible embodiments, the heat exchange structure can adopt heat exchange structures such as tube bundle type, plate type, cross flow type, etc. Any structural model that meets the condition of the proportion of the solid area at the cross section in the above design method can be used as the heat exchange structure. The length of the heat exchange structure must be less than the length of the heat exchanger housing.

[0063] In some possible embodiments, the shape of the heat exchanger housing is not limited and can be designed according to needs. An irregular shape housing or a regular shape housing can be selected. If a regular shape housing is selected, it can be cylindrical or elliptical, etc.

[0064] Without loss of generality, two embodiments will be described in detail below.

[0065] Embodiment 1:

[0066] Design objective: Design a pure air cooling device with a circular cross section, and the maximum operating Mach number is 4.2.

[0067] Design conditions: The air flow velocities at the inlet and outlet of the cooling device are Mach 0.2, and the gas flow velocity in the heat exchange structure is maintained at Mach 0.3; the total temperature of the air to be pre-cooled is the stagnation temperature of the oncoming air corresponding to Mach 4.2, and the flow rate is assumed to be 2 kg / s (before flowing into the cooling device, the high-speed oncoming air at Mach 4.2 is decelerated to Mach 0.2 at the inlet of the cooling device); the static pressure of the air at the inlet of the heat exchange structure is 1.3 atm, the static pressure at the outlet is 1.0 atm, and the temperature is 350 K.

[0068] Analyze the design parameters of the heat exchange structure according to the above design conditions; assume that when the oncoming flow rate increases to 4 kg / s or decreases to 1 kg / s, what should the inlet and outlet diameters of the heat exchange structure be respectively.

[0069] Design process:

[0070] Design the high-temperature gas cooling device into a three-section form of continuous connection with a Mach 0.2 section at the inlet, and then due to the existence of ( Figure 1 The dark gray part in the middle of the pipeline) in the heat exchange structure, part of the air flow path is blocked, and the air flow velocity increases to Mach 0.3, and then the outlet of the cooling device returns to a Mach 0.2 section without a heat exchange structure. Without loss of generality, the heat exchange structure is designed as a countercurrent tube bundle type here.

[0071] Since the Mach number in the entire air channel does not exceed the maximum Mach number of incompressible flow, which is 0.3, the detailed computational fluid dynamics (CFD) design after the preliminary design can be carried out using an incompressible flow solver.

[0072] Step 301. According to the analysis of the design conditions, the cross-sectional areas at the inlet and outlet of the heat exchange structure can be obtained by using the air flow area formula at the inlet and outlet, and by organizing the high-temperature gas density and absolute velocity at the inlet and outlet of the heat exchange structure model.

[0073] Mach 4.2 corresponds to a total incoming air temperature of approximately 1000K.

[0074] The air flow area calculation formulas for the inlet and outlet of the heat exchange structure are as follows:

[0075] m = ρ1·s1·v1 = ρ2·s2·v2 = 2 kg / s (this formula is also applicable to the calculation of the air flow area at the inlet and outlet of the cooling device)

[0076] In the formula, m represents the air flow rate, ρ1 represents the air density at the inlet of the heat exchange structure, s1 represents the cross-sectional area at the inlet of the heat exchange structure, v1 represents the flow velocity of the high-temperature gas at the inlet of the heat exchange structure; ρ2 represents the air density at the outlet of the heat exchange structure, s2 represents the cross-sectional area at the outlet of the heat exchange structure, and v2 represents the flow velocity of the high-temperature gas at the outlet of the heat exchange structure.

[0077] At 1 atm, the air density at 1000K is 0.3482 kg / m 3 , so at 1.3 atm

[0078] ρ1 = 0.3482 * 1.3 = 0.4527 kg / m^3

[0079] At 1 atm, the air density ρ2 at 350K is 0.9950 kg / m 3 .

[0080] The speed of sound in air at 1000K is: C1 = (γRT) 1 / 2 = 633 m / s. In the formula, γ represents the specific heat ratio of air, R represents the air gas constant, and T represents the static air temperature.

[0081] The speed of sound in air at 350K is: C2 = (γRT) 1 / 2 = 374 m / s. (It is estimated that the air-side inlet temperature of the cooling device is 1000K, and the outlet temperature of the cooling device is 350K.)

[0082] Therefore, the absolute values of the inlet and outlet velocities at the inlet and outlet of the heat exchange structure are respectively:

[0083] v1 = 633 * 0.3 = 189.9 m / s, v2 = 374 * 0.3 = 112.2 m / s. (The 0.3 in the formula here is the Mach number of the flow velocity inside the heat exchange structure)

[0084] Calculated: s1 = 2 / (ρ1v1) = 0.02326 square meters, s2 = 2 / (ρ2v2) = 0.0179 square meters.

[0085] Step 302: According to the analysis of the design conditions, by sorting out the high-temperature gas density and the absolute value of the velocity at the air inlet and outlet of the cooling device model, the cross-sectional area at the air inlet and outlet of the cooling device model is obtained.

[0086] In Embodiment 1, the air flow velocities at the air inlet and outlet of the cooling device are 0.2 Mach. Therefore, the absolute values of the air inlet and outlet velocities at the air inlet and outlet of the cooling device are respectively:

[0087] v 01 = 633 * 0.2 = 126.6 m / s, v 02 = 374 * 0.2 = 74.8 m / s.

[0088] The cross-sectional areas at the air inlet and outlet of the cooling device are: s 01 = 2 / (ρ1v 01 ) = 0.03490 square meters, s 02 = 2 / (ρ2v 02 ) = 0.02687 square meters.

[0089] Step 303: According to the results of Step 301 and Step 3022, the proportion of the solid area of the heat exchange structure model in the cross-section perpendicular to the high-temperature gas flow direction at the air inlet and outlet of the heat exchange structure model is obtained.

[0090] The cross-section of the cooling device is a circular cross-section. According to the calculation of the cross-sectional area of the circle, the diameters of the air inlet and outlet of the cooling device can be obtained as follows:

[0091] Air inlet diameter: 0.211 m, that is, 211 mm,

[0092] Air outlet diameter: 0.185 m, that is, 185 mm.

[0093] The proportion of the solid area in the cross-section of the heat exchange structure at the air inlet is (0.03490 - 0.02326) / 0.03490 = 0.33.

[0094] The proportion of the solid area in the cross-section of the heat exchange structure at the air outlet is (0.02687 - 0.0179) / 0.02687 = 0.33.

[0095] The key innovation point of the present invention is that the proportion of the solid area (the area of the wall thickness of the heat dissipation fins + the cross-sectional area of the coolant channel) of each arbitrary cross-section of the heat exchange structure perpendicular to the high-temperature gas flow direction in the heat exchange structure (i.e., Figure 2The medium and dark part) maintains the same value as the cross-section of the intake and outlet of the heat exchange structure, so as to ensure that the flow velocity at each cross-section inside the heat exchange structure remains the same Mach number. And the Mach number of the flow velocity inside the heat exchange structure can be freely changed according to requirements. The specific adjustment method is to use the basic theory of aerodynamics and combine the gas physical properties to calculate the target proportion value of the solid part in the heat exchange structure.

[0096] Let the Mach number of the intake and outlet of the heat exchange structure model be Ma1, and the Mach number of the intake and outlet of the cooling device model be Ma2. Then the calculation formula for the proportion of the solid area in the heat exchange structure model is: under the condition that the inlet and outlet air flow temperatures and pressures of the heat exchange structure and the cooling device are the same, f = 1 - y(Ma2) / y(Ma1), where y(Ma) = 1 / Ma·((1 + 0.2·Ma 2 ) / 1.2) 3 , and the value of f is equal to the proportion of the solid area in the heat exchange structure model.

[0097] In this embodiment, this proportion value is 0.33, so as to ensure that the designed Mach number of the internal flow velocity is 0.3. If other conditions remain unchanged and the designed Mach number of the flow velocity in the heat exchanger is adjusted to 0.4, then the proportion value of the solid area in the heat exchange structure needs to be increased to 0.46, and the inlet and outlet sizes of the cooling device after the flow rate changes can be easily obtained according to the geometric relationship.

[0098] The design results are shown in Table 3:

[0099] Table 3 - Design parameters of the air cooling device (designed with an equal Mach number of 0.3)

[0100]

[0101] Since the highest Mach number in the entire air flow path does not exceed 0.3, far from the maximum flow rate working point of the gas flow velocity Mach number of 1.0, it can be ensured that no choking phenomenon will occur.

[0102] On the other hand, when specifically constructing the heat exchange structure inside the air cooling device, based on the equal Mach number design proposed by the present invention, the proportion of the solid area of the heat exchange structure at each cross-section is locked at 33% (corresponding to the designed Mach number of 0.3). This strong constraint can make the variational method or other mathematical and physical methods more targeted when specifically optimizing the design of the heat exchange structure, and it is also more comparable when comparing the heat exchange effects under different specific heat exchange structures.

[0103] In addition, since the proportion of the solid area of the heat exchange structure is a definite 33%, the weight per unit length of the air cooling device can be obtained by multiplying the total volume (1 m per unit length) determined by the outer contour size, multiplying by the density of the material used in the cooling device, and then multiplying by 0.33.

[0104] Embodiment 2:

[0105] Design objective: A heat exchanger with an irregular cross-sectional shape (different from the circular cross-section in the first embodiment and more general).

[0106] Design conditions: The total temperature at the air inlet of the cooling device is 1000K, the static pressure is 1.3 atm, and the Mach number of the gas flow velocity at the inlet is 0.4; the equivalent Mach number along the air flow path, i.e., the Mach number of the gas flow velocity in the heat exchange structure, is 0.6 (taking into account heat transfer efficiency and pressure drop constraints).

[0107] Design result: According to the equal Mach number design method of the present invention, it can be calculated that the proportion of the air channel in each cross-section of the heat exchange structure in the air pre-cooler is 75%, and the corresponding proportion of the solid part is 25%.

[0108] The dimensions of the cooling device corresponding to different flow rates are shown in Table 4:

[0109] Table 4 Dimensions and mass prediction of the cooling device (designed with an equal Mach number of 0.4)

[0110]

[0111] As can be seen from Table 4, under the equal Mach number design conditions, the proportion of the solid area in each cross-section of the heat exchange structure is the same. Therefore, when the density of the manufacturing material of the cooling device is known, the weight of the heat exchange structure can be calculated from the proportion of the solid area, providing a reference for the design of the heat exchange structure.

[0112] Objectively, the increasingly mature additive manufacturing technology (such as 3D printing) provides a way to realize the processing, forming and practical application of the gas cooling device designed with an equal Mach number.

[0113] The above embodiments are only exemplary embodiments of the present application and are not used to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present application, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present application.

Claims

1. A design method for high-temperature gas cooling with equal Mach number, characterized in that, The method steps include: Step 100: Establish a cooling device model, including a housing model and a heat exchange structure model fixed within the housing model. Coolant is passed through the interior of the heat exchange structure model, and the gap between the heat exchange structure model and the housing model serves as an air channel through which high-temperature gas passes. Step 200: Import the given design conditions into the data analysis unit. The design conditions include the Mach number of the high-temperature gas flow velocity at the inlet and outlet of the cooling device model, the air pressure and temperature at the inlet and outlet of the heat exchange structure model, and the Mach number of the high-temperature gas flow velocity within the air channel between the inlet and outlet of the heat exchange structure model. Step 300: In the data analysis unit, a data analysis criterion is set: the ratio of the solid area of the heat exchange structure model in the front and rear adjacent cross-sections perpendicular to the high-temperature gas flow direction within the cooling device model to the area of the intercepted cross-section is the same. The solid area is the cross-sectional area of the heat exchange structure model. Based on the given design conditions and in accordance with the data analysis criterion, analyze to obtain the cross-sectional areas of the inlet and outlet of the heat exchange structure model in the cross-section perpendicular to the high-temperature gas flow direction, and the cross-sectional areas of the inlet and outlet of the cooling device model in the cross-section perpendicular to the high-temperature gas flow direction. Step 400: Determine the size of the cooling device model and the size of the heat exchange structure model based on the cross-sectional areas of the inlet and outlet of the heat exchange structure model and the cross-sectional areas of the inlet and outlet of the cooling device model. The analysis process within the data analysis unit is as follows: Step 301: Analyze to obtain the cross-sectional areas at the inlet and outlet of the heat exchange structure model based on the given design conditions. Step 302: Analyze to obtain the cross-sectional areas at the inlet and outlet of the cooling device model based on the given design conditions. Step 303: Based on the results of Step 301 and Step 302, obtain the proportion of the solid area of the heat exchange structure model in the cross-section perpendicular to the high-temperature gas flow direction at the inlet and outlet of the heat exchange structure model.

2. A design method for high-temperature gas cooling with equal Mach number according to claim 1, characterized in that, The Mach number of the high-temperature gas flow velocity within the heat exchange structure model in Step 200 is the same in segments or the same throughout from the inlet of the heat exchange structure model to the outlet of the heat exchange structure model.

3. A design method for high-temperature gas cooling with equal Mach number according to claim 1, characterized in that, The data analysis criterion in Step 300 is specifically: at the front and rear adjacent cross-sections within the cooling device model perpendicular to the high-temperature gas flow direction, the ratio of the solid area of the heat exchange structure model to the total cross-sectional area is the same as the ratio of the solid area at the inlet and outlet cross-sections of the heat exchange structure model.

4. A method for designing a high-temperature gas cooling with equal Mach number according to claim 3, characterized in that, The Mach number of the high-temperature gas flow velocity at any cross-section within the heat exchange structure model perpendicular to the high-temperature gas flow direction is the same.

5. A design method for high-temperature gas cooling with equal Mach number according to claim 1, characterized in that, Based on the given Mach number of the high-temperature gas flow velocity within the heat exchange structure model, according to the basic theory of aerodynamics and the physical properties of high-temperature gas, the proportional value of the proportion of the solid area of the heat exchange structure model at any cross-section perpendicular to the high-temperature gas flow direction within the cooling device model can be calculated.

6. A design method for high-temperature gas cooling with equal Mach number according to claim 1, characterized in that The heat exchange structure model selects one of a tube bundle structure, a cross-flow structure, or a plate structure, and the length of the heat exchange structure model is less than the length of the cooling device model.

7. A high-temperature gas cooling device with equal Mach number, characterized in that, Adopt a high-temperature gas cooling design method with equal Mach number as described in any one of claims 1-6, including Heat exchanger housing and heat exchange structure. The heat exchange structure is fixed inside the heat exchanger housing, and the gap between the heat exchange structure and the inside of the heat exchanger housing forms an air passage. A coolant flows through the heat exchange structure to cool down. At any cross-section perpendicular to the flow direction of the high-temperature gas inside the heat exchanger housing, the proportion of the solid area of the heat exchange structure in the total cross-sectional area is the same as the proportion of the solid area at the inlet and outlet cross-sections of the heat exchange structure.

8. A high-temperature gas cooling device with equal Mach number according to claim 7, characterized in that, The heat exchange structure includes a plurality of coolant channels through which the coolant flows and a plurality of heat dissipation fins. The coolant channels are fixed inside the heat exchanger housing through the heat dissipation fins. An air passage is formed by connecting each coolant channel to other coolant channels and to the heat exchanger housing by the heat dissipation fins. At any cross-section perpendicular to the flow direction of the high-temperature gas, the cross-sectional areas of the heat dissipation fins and the coolant channels are solid areas.

9. An isentropic high-temperature gas cooling device according to claim 7, characterized in that, The heat exchanger housing is an irregular-shaped housing or a regular-shaped housing.

10. A high-temperature gas cooling device with equal Mach number according to claim 7, characterized in that, The heat exchange structure is selected from one of a tube bundle structure, a cross-flow structure, or a plate structure.

11. A high-temperature gas cooling device with equal Mach number according to any one of claims 8-10, characterized in that, The length of the heat exchange structure is less than the length of the heat exchanger housing.

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