Integrated titanium alloy plate-fin heat exchanger core body design method and core body

Abstract

The invention discloses an integrated titanium alloy plate-fin heat exchanger core body design method and a core body. During design, a thermal medium and a cold medium are determined firstly; according to the types of the heat media, parallel connection or series connection arrangement of flow channels where adjacent heat media are located in the core is determined; calculating the heat transfer areas required by all the heat media, and determining the proportion of the heat transfer areas required by all the heat media; for the heat media of the same type, the flow channels where the heat media with the proportion not smaller than 30% are located are arranged in the core body in parallel; serial connection or parallel connection is determined according to the inlet and outlet positions of the heat medium and the relation between the inlet and outlet positions of the heat medium and the position of an adjacent heat medium inlet; the flow channels where the hot media are located and the flow channels where the cold media are located are arranged at intervals, and the flowing directions intersect and are isolated spatially. And then determining whether the flow channel of the adjacent heat medium needs to be separated by a physical isolation structure and determining the extension length of the two sides of the flow channel. The heat exchanger core can be efficiently integrated and has high heat exchange performance and high reliability.

Description

Technical Field

[0001] The invention relates to the technical field of plate-fin heat exchangers, and in particular to a core design method and a core of an integrated titanium alloy plate-fin heat exchanger. Background Art

[0002] Titanium alloy plate-fin heat exchangers are widely used in the maritime industry due to their good seawater resistance. With the development of military vehicle technology, some military vehicles are required to have amphibious functions and be used in offshore waters. Their cooling systems need to use titanium alloy heat exchangers that are resistant to seawater corrosion. Limited by the space in the vehicle's power compartment, the titanium alloy heat exchanger required has a multi-media integrated structure. When the vehicle is traveling in offshore waters, seawater is used to cool the coolant, transmission oil, water transmission oil and other media required by the vehicle. The media that need to be cooled are not limited to the coolant, transmission oil and water transmission oil mentioned above, but can also include the coolant, fuel, and pressurized air of the motor system.

[0003] When designing a multi-media integrated core, not only the heat dissipation requirements must be considered, but also the temperature requirements, working pressure requirements, flow requirements, flow resistance requirements, etc. of the medium to be cooled, and a comprehensive integrated design must be performed.

[0004] At present, the core of multi-media titanium alloy plate-fin heat exchanger is mainly separated by multiple rows of seals for cooling different media, and the core is produced by vacuum brazing. When welding the heads of different media, the welding parts of the heads and the core are easily affected by the high temperature of welding, which may cause welding defects in the core and cause mixing of the internal media. Summary of the invention

[0005] In view of this, the present invention provides an integrated titanium alloy plate-fin heat exchanger core design method and core, which can enable the heat exchanger core to be efficiently integrated and have higher heat exchange performance and high reliability.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for designing an integrated titanium alloy plate-fin heat exchanger core, the design method steps are as follows:

[0008] Step 1: The medium that needs to dissipate heat on the vehicle is defined as the hot medium, and the medium that performs heat dissipation is defined as the cold medium;

[0009] Step 2: If the types of heat media are different, the flow channels where adjacent heat media are located are arranged in parallel in the core; if the types of heat media are the same, the flow channels where adjacent heat media are located can be arranged in parallel or in series in the core;

[0010] Step 3: Calculate the heat transfer area required by all heat media and determine the proportion of the heat transfer area required by each heat medium in the total area; the sum of the heat transfer areas required by all heat media is the total area;

[0011] Step 4: For the same type of heat medium, the flow channels where the heat medium whose heat transfer area accounts for not less than 30% of the total area are arranged in parallel in the core; for the heat medium whose heat transfer area accounts for less than 30% of the total area, the flow channels where the heat medium is located are determined to be connected in series or in parallel in the core according to the inlet and outlet positions of the heat medium and the relationship between the inlet and outlet positions and the inlet and outlet positions of the adjacent heat medium; the flow channels where the heat medium is located are arranged at intervals from the flow channels where the cold medium is located, and the flow directions are intersected in space and separated by partitions;

[0012] Step 5: Determine whether adjacent heat medium flow channels need to be separated by a physical isolation structure according to the type of heat medium;

[0013] Step six, determine the length of the physical isolation structure extending from both sides of the inlet and outlet of the flow channel where the heat medium is located.

[0014] Furthermore, in step 3, the outlet temperatures of the cold side and the hot side are calculated according to the heat dissipation, inlet temperature and flow rate of the given hot medium and cold medium, and the outlet temperature is calculated using the specific heat capacity formula:

[0015] Q=mCpΔt

[0016] In the formula, Q is the heat dissipation, m is the mass flow rate, Cp is the constant pressure specific heat, and Δt is the inlet and outlet temperature difference;

[0017] The heat transfer area is calculated according to the outlet temperature according to the heat exchanger design method.

[0018] Furthermore, in the step 4, the flow channels where the heat medium is located are connected in series from low to high according to the outlet temperature.

[0019] Furthermore, in step 5, if the two adjacent heat media are of different types, a physical isolation structure needs to be adopted; if the two adjacent heat media are of the same type, no physical isolation structure is required.

[0020] Furthermore, when the physical isolation structure and the core body head are welded by argon arc welding, the length in step 5 is determined according to the following formula:

[0021]

[0022] Where L is the length, T1 is the melting temperature of the titanium alloy, T2 is the melting temperature of the solder, λ is the thermal conductivity of the titanium alloy, δ is the thickness of the physical isolation structure, U is the welding voltage, and I is the welding current.

[0023] Furthermore, the physical isolation structure is a side guard plate.

[0024] The present invention also provides an integrated titanium alloy plate-fin heat exchanger core, including a cold medium flow channel, a hot medium flow channel I, a hot medium flow channel II, a hot medium flow channel III and a side guard plate; the cold medium flow channel, the hot medium flow channel I, the hot medium flow channel II, the hot medium flow channel III and the side guard plate are all titanium alloy;

[0025] The heat medium flow channel I, heat medium flow channel II, and heat medium flow channel III are arranged in parallel in the vertical direction from bottom to top, and side guard plates are arranged between adjacent heat medium flow channels and at the outermost sides of heat medium flow channels I and heat medium flow channels III, and the side guard plates extend from both sides of the flow channel inlet and outlet to a set length; the heat medium flow channel I, heat medium flow channel II, and heat medium flow channel III each include several layers of hot runners, cold medium flow channels are arranged between adjacent hot runners and isolated by partitions, and the flow directions of the media in the hot runner and the cold medium flow channels intersect with each other.

[0026] Furthermore, the cold medium in the cold medium flow channel is seawater, the hot medium in the hot medium flow channel I is land transmission oil, the hot medium in the hot medium flow channel II is water transmission oil, and the hot medium in the hot medium flow channel III is coolant.

[0027] Furthermore, the set length is:

[0028]

[0029] Where L is the length, T1 is the melting temperature of the titanium alloy, T2 is the melting temperature of the solder, λ is the thermal conductivity of the titanium alloy, δ is the thickness of the physical isolation structure, U is the welding voltage, and I is the welding current.

[0030] Beneficial effects:

[0031] 1. The design method of the present invention determines that the hot side medium adopts a combination of series, parallel or series-parallel connection and the extension length of the physical isolation structure. The structure is efficiently integrated and can meet the requirements of efficient, compact and reliable use of the heat exchanger when the vehicle is used in sea areas.

[0032] 2. The present invention determines whether a physical isolation structure is required according to the type of heat medium, thereby preventing vehicle failures caused by mixing of the media.

[0033] 3. The present invention limits the extension length of the physical isolation structure, so that the welding position of the core and the head is far away from the core, effectively avoiding the problem of the two heat media mixing with each other and causing vehicle failure when welding defects occur at the root of the core. At the same time, it also reduces the welding difficulty and improves the reliability of the titanium alloy plate-fin heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the core structure of the present invention.

[0035] Figure 2 It is a schematic diagram of the structure of the core body and the head after welding of the present invention.

[0036] Figure 3 It is a cross-sectional view of the core body and the head after welding of the present invention.

[0037] Figure 4 This is a comparison diagram of the welding positions of the core body of the present invention and the traditional one.

[0038] Among them, 1-side guard plate I; 2-side guard plate II; 3-side guard plate III; 4-side guard plate IV; 5-partition; 6-seawater side fin; 7-seawater side seal; 8-hot side fin; 9-hot side seal; 10-seawater side water outlet chamber; 11-coolant water outlet chamber; 12-water transmission oil outlet chamber; 13-transmission oil outlet chamber; 14-seawater side water inlet chamber; 15-transmission oil inlet chamber; 16-water transmission oil inlet chamber; 17-coolant water inlet chamber. DETAILED DESCRIPTION

[0039] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0040] The present invention provides a method for designing an integrated titanium alloy plate-fin heat exchanger core, and the steps of the design method are as follows:

[0041] Step 1: The medium that needs to dissipate heat on the vehicle is defined as the hot medium, and the medium that performs heat dissipation is defined as the cold medium.

[0042] Step 2: Determine the layout of the flow channels where the heat medium is located in the core according to the type of heat medium: if the types of heat medium are different, the flow channels where the heat medium is located are arranged in parallel in the core; if the types of heat medium are the same, the flow channels where the heat medium is located can be arranged in parallel or in series in the core.

[0043] For example: two kinds of oil can be connected in series or in parallel; two kinds of coolants, generally one is a low-temperature coolant and the other is a high-temperature coolant, which can be connected in series or in parallel. When a series structure is adopted, the low-temperature coolant passes through first, and then the high-temperature coolant.

[0044] Step three, calculate the outlet temperature of the cold side and the hot side according to the heat dissipation, inlet temperature and flow rate of the given hot medium and cold medium, and calculate the heat transfer area required for all heat media according to the heat exchanger design method, and determine the proportion of the heat transfer area required for each heat medium in the total area; the sum of the heat transfer areas required for all heat media is the total area; the number of layers and length required in the core can be obtained from the heat transfer area.

[0045] Specifically, the outlet temperature is calculated using the specific heat capacity formula:

[0046] Q=mCpΔt

[0047] Where Q is the heat dissipation, m is the mass flow rate, Cp is the constant pressure specific heat, and Δt is the inlet and outlet temperature difference.

[0048] Step 4: Based on step 2, for the same type of heat medium, the flow channels where the heat medium with a heat transfer area accounting for not less than 30% of the total area are arranged in parallel in the core; for the heat medium with a heat transfer area accounting for less than 30% of the total area, the flow channels where the heat medium is located are determined to be connected in series or in parallel in the core according to the inlet and outlet positions of the heat medium and the relationship between the inlet and outlet positions and the inlet and outlet positions of the adjacent heat medium; the flow channels where the heat medium is located are arranged at intervals from the flow channels where the cold medium is located, and the flow directions thereof intersect each other in space and are isolated by partitions 5;

[0049] Specifically, if the flow channels where the heat medium is located need to be connected in series, they are connected in series from low to high outlet temperatures.

[0050] Step 5: Determine whether adjacent heat medium flow channels need to be separated by a physical isolation structure according to the type of heat medium;

[0051] Specifically, two adjacent heat media of different types need to be physically isolated. If coolant and oil are mixed, it will cause vehicle failure, so coolant and oil need to be physically isolated; if pressurized air and water or oil are mixed, it will also cause vehicle failure, so a physical isolation structure should also be used between pressurized air and water or oil.

[0052] There is no need for physical isolation structure when two adjacent heat media are of the same type. There is no need for physical isolation structure between two oils or two coolants.

[0053] Step six, determine the length of the physical isolation structure extending from both sides of the inlet and outlet of the flow channel where the heat medium is located.

[0054] Specifically, when the physical isolation structure and the core body head are welded by argon arc welding DC, the length in step 5 is determined according to the following formula:

[0055]

[0056] Where L is the length, T1 is the melting temperature of titanium alloy, T2 is the melting temperature of solder, λ is the thermal conductivity of titanium alloy, δ is the thickness of the physical isolation structure, U is the welding voltage, and I is the welding current. Generally, L is not less than 10 mm.

[0057] This can determine whether the heat medium is connected in series, in parallel or in combination in the core and the extension length of the material isolation structure. The material isolation structure can adopt side guard plates.

[0058] Based on the above-mentioned integrated titanium alloy plate-fin heat exchanger core design method, the present invention also provides an integrated titanium alloy plate-fin heat exchanger core, which includes a cold medium flow channel, a hot medium flow channel I, a hot medium flow channel II, a hot medium flow channel III, a side guard plate and a partition 5; the cold medium flow channel, the hot medium flow channel I, the hot medium flow channel II, the hot medium flow channel III and the side guard plate are all titanium alloy.

[0059] The heat medium flow channel I, the heat medium flow channel II, and the heat medium flow channel III are arranged in parallel in the vertical direction from bottom to top, and side guard plates are arranged between adjacent heat medium flow channels and at the outermost sides of the heat medium flow channels I and the heat medium flow channels III, and the side guard plates extend from both sides of the flow channel inlet and outlet to a set length; the heat medium flow channel I, the heat medium flow channel II, and the heat medium flow channel III each include several layers of hot runners, and cold medium flow channels are arranged between adjacent hot runners and isolated by partitions 5, that is, one layer of cold medium flow channel and one layer of hot runner, and the flow directions of the media in the hot runner and the cold medium flow channel intersect with each other.

[0060] The set length of the side guard plate extending from both sides of the flow channel inlet and outlet is:

[0061]

[0062] Wherein, L is the length (mm), T1 is the melting temperature of titanium alloy (℃), T2 is the melting temperature of solder (℃), λ is the thermal conductivity of titanium alloy (W / m·K), δ is the thickness of the physical isolation structure (mm), U is the welding voltage (V), and I is the welding current (A).

[0063] like Figure 1 As shown, in this embodiment, the cold medium in the cold medium flow channel is seawater, the hot medium in the hot medium flow channel I is land transmission oil, the hot medium in the hot medium flow channel II is water transmission oil, and the hot medium in the hot medium flow channel III is coolant. The side guard plate includes side guard plate I1, side guard plate II2, side guard plate III3, and side guard plate IV4. The hot medium flow channel I, hot medium flow channel II, and hot medium flow channel III are all composed of hot side fins 8 and hot side seals 9, and the cold medium flow channel is composed of seawater side fins 6 and seawater side seals 7. A layer of hot side fins 8 and a layer of seawater side fins 6 are stacked and separated by a partition 5 and then formed into a whole by vacuum brazing. The bottom surface of the heat medium flow channel I is a side guard plate I1, the side guard plate II2 is between the heat medium flow channel I and the heat medium flow channel II, the side guard plate III3 is between the heat medium flow channel II and the heat medium flow channel III, and the top surface of the heat medium flow channel III is a side guard plate IV4. The lengths of the side guard plates I1, II2, III3 and IV4 in the hot side medium inlet and outlet directions are all greater than the length of the core, and the extended length is L.

[0064] like Figure 2 , Figure 3As shown, after the core is vacuum brazed, the ends on both sides of the seawater inlet and outlet are first welded to form a seawater side water inlet chamber 14 and a seawater side water outlet chamber 10, which are welded to the core in a traditional welding manner; then the ends on both sides of the transmission oil inlet and outlet are welded in sequence to form a transmission oil inlet chamber 15 and a transmission oil outlet chamber 13, and the welding positions of the transmission oil inlet and outlet chambers 15 and 13 with the core are mainly in the length direction of the side guard plates Ⅰ1 and Ⅱ2; the ends on both sides of the water transmission oil inlet and outlet are welded to form a water transmission oil inlet chamber 16 and a water transmission oil outlet chamber 12, and the welding positions of the transmission oil inlet and outlet chambers 16 and 12 with the core are mainly in the length direction of the side guard plates Ⅱ2 and Ⅲ3; the ends on both sides of the coolant inlet and outlet are welded to form a coolant water inlet chamber 17 and a coolant water outlet chamber 11, and the welding positions of the transmission oil inlet and outlet chambers 11 with the core are mainly in the length direction of the side guard plates Ⅲ3 and Ⅳ4; this welding form avoids multiple welding at the brazing positions on the core, reduces the possibility of welding defects such as leakage, slag inclusion, and pores caused by high welding temperature, avoids mixing between media, and realizes physical isolation of multiple media.

[0065] The working principle of the integrated titanium alloy plate-fin heat exchanger core is: the transmission oil flow channel is separated by the side guard plate Ⅰ1 and the side guard plate Ⅱ2; the water transmission oil flow channel is separated by the side guard plate Ⅱ2 and the side guard plate Ⅲ3; the coolant flow channel is separated by the side guard plate Ⅲ3 and the side guard plate Ⅳ4. During welding, the main welding positions are the edges of the side guard plates Ⅰ1, Ⅱ2, Ⅲ3 and Ⅳ4, avoiding multiple welding with the root of the core. Figure 4 As shown, compared with the traditional welding position A between the core body and the head, the welding position B between the core body and the head is set on the side guard plate extending from the core body, avoiding welding at the root of the core body.

[0066] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing an integrated titanium alloy plate-fin heat exchanger core, characterized in that: The design method steps are as follows: Step 1: The medium that needs to dissipate heat on the vehicle is defined as the hot medium, and the medium that performs heat dissipation is defined as the cold medium; Step 2: If the types of heat media are different, the flow channels where adjacent heat media are located are arranged in parallel in the core; if the types of heat media are the same, the flow channels where adjacent heat media are located can be arranged in parallel or in series in the core; Step 3: Calculate the heat transfer area required by all heat media and determine the proportion of the heat transfer area required by each heat medium in the total area; the sum of the heat transfer areas required by all heat media is the total area; Step 4: For the same type of heat medium, the flow channels where the heat medium whose heat transfer area accounts for not less than 30% of the total area are arranged in parallel in the core; for the heat medium whose heat transfer area accounts for less than 30% of the total area, the flow channels where the heat medium is located are determined to be connected in series or in parallel in the core according to the inlet and outlet positions of the heat medium and the relationship between the inlet and outlet positions and the inlet and outlet positions of the adjacent heat medium; the flow channels where the heat medium is located are arranged at intervals from the flow channels where the cold medium is located, and the flow directions are intersected in space and separated by partitions; Step 5: Determine whether adjacent heat medium flow channels need to be separated by a physical isolation structure according to the type of heat medium; Step six, determine the length of the physical isolation structure extending from both sides of the inlet and outlet of the flow channel where the heat medium is located.

2. The integrated titanium alloy plate-fin heat exchanger core design method according to claim 1, characterized in that: In step 3, the outlet temperatures of the cold side and the hot side are calculated according to the heat dissipation, inlet temperature and flow rate of the given hot medium and cold medium. The outlet temperature is calculated using the specific heat capacity formula: Q=mCpΔt In the formula, Q is the heat dissipation, m is the mass flow rate, Cp is the constant pressure specific heat, and Δt is the inlet and outlet temperature difference; The heat transfer area is calculated according to the outlet temperature according to the heat exchanger design method.

3. The integrated titanium alloy plate-fin heat exchanger core design method according to claim 1, characterized in that: In the step 4, the flow channels where the heat medium is located are connected in series from low to high according to the outlet temperature.

4. The integrated titanium alloy plate-fin heat exchanger core design method according to claim 1, characterized in that: In step 5, if the two adjacent heat media are of different types, a physical isolation structure needs to be used; if the two adjacent heat media are of the same type, no physical isolation structure is required.

5. The integrated titanium alloy plate-fin heat exchanger core design method according to claim 1 or 4, characterized in that: When the physical isolation structure and the core body are welded by argon arc welding and direct current welding, the length in step 5 is determined according to the following formula: Where L is the length, T1 is the melting temperature of the titanium alloy, T2 is the melting temperature of the solder, λ is the thermal conductivity of the titanium alloy, δ is the thickness of the physical isolation structure, U is the welding voltage, and I is the welding current.

6. The integrated titanium alloy plate-fin heat exchanger core design method according to claim 5, characterized in that: The physical isolation structure is a side guard plate.

7. An integrated titanium alloy plate-fin heat exchanger core, characterized in that: Including cold medium flow channel, hot medium flow channel I, hot medium flow channel II, hot medium flow channel III and side guard plates; cold medium flow channel, hot medium flow channel I, hot medium flow channel II, hot medium flow channel III and side guard plates are all titanium alloy; The heat medium flow channel I, heat medium flow channel II, and heat medium flow channel III are arranged in parallel in the vertical direction from bottom to top, and side guard plates are arranged between adjacent heat medium flow channels and at the outermost sides of heat medium flow channels I and heat medium flow channels III, and the side guard plates extend from both sides of the flow channel inlet and outlet to a set length; the heat medium flow channel I, heat medium flow channel II, and heat medium flow channel III each include several layers of hot runners, cold medium flow channels are arranged between adjacent hot runners and isolated by partitions, and the flow directions of the media in the hot runner and the cold medium flow channels intersect with each other.

8. The integrated titanium alloy plate-fin heat exchanger core design method according to claim 7, characterized in that: The cold medium in the cold medium flow channel is seawater, the hot medium in the hot medium flow channel I is land transmission oil, the hot medium in the hot medium flow channel II is water transmission oil, and the hot medium in the hot medium flow channel III is coolant.

9. The integrated titanium alloy plate-fin heat exchanger core according to claim 7 or 8, characterized in that: The set length is: Where L is the length, T1 is the melting temperature of the titanium alloy, T2 is the melting temperature of the solder, λ is the thermal conductivity of the titanium alloy, δ is the thickness of the physical isolation structure, U is the welding voltage, and I is the welding current.

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