New energy commercial vehicle cooling system with spray evaporation and performance test method thereof

Abstract

The invention relates to the technical field of hydrogen fuel automobile cooling modules, and discloses a new energy commercial vehicle cooling system with spraying evaporation, which comprises a sample piece mounting panel for mounting a radiator sample piece, a spraying system is arranged on the windward side of the sample piece mounting panel, and a plurality of inlet air temperature sensors are arranged on the outer side of the spraying system. And a plurality of air outlet temperature sensors are arranged on the air outlet side of the sample piece mounting panel. The invention further discloses a performance test method of the new energy commercial vehicle cooling system with the spray evaporation function. According to the new energy commercial vehicle cooling system with the spraying evaporation function and the performance test method thereof, evaporation heat absorption of water which is a reaction product of a hydrogen fuel cell is adopted, more materials are saved compared with a traditional cooling module on the premise of exerting the same heat exchange performance, data support is provided for design of a whole vehicle heat management system through the performance test method, and the new energy commercial vehicle cooling system is suitable for popularization and application. And the design of a heat exchanger product is optimized to the greatest extent.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel vehicle cooling modules, and in particular to a new energy commercial vehicle cooling system with spray evaporation and a performance test method thereof. Background Art

[0002] The research and development of new energy vehicles and related products has always been the focus of major OEMs and parts companies. As the energy core of new energy vehicles, batteries, especially batteries with hydrogen as the main fuel, are receiving more and more attention. They provide the energy required for normal operation of the car and generate a lot of heat, which needs to be cooled by the cooling system. As a key component of the automotive thermal management system, the automotive heat exchanger ensures that the car always runs in the appropriate temperature range under all working conditions through heat exchange in the working system. Its heat exchange performance directly affects whether the new energy vehicle can operate normally.

[0003] In addition, the product of hydrogen consumption is water, which can help cool the fuel cell. If it is not used, it will cause energy waste. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned technologies and provide a new energy commercial vehicle cooling system with spray evaporation and a performance test method thereof. The evaporation of water, a product of the hydrogen fuel cell reaction, is used to absorb heat. Under the premise of achieving the same heat exchange performance, it saves more materials than traditional cooling modules. In addition, the performance test method is used to provide data support for the design of the vehicle thermal management system, thereby optimizing the design of the heat exchanger product to the greatest extent.

[0005] To achieve the above-mentioned purpose, the cooling system for new energy commercial vehicles with spray evaporation designed by the present invention includes a sample mounting panel for mounting a radiator sample, a spray system is provided on the windward side of the sample mounting panel, a plurality of air inlet temperature sensors are provided on the outside of the spray system, and a plurality of air outlet temperature sensors are provided on the air outlet side of the sample mounting panel.

[0006] Preferably, the spray system comprises a water storage tank for collecting water generated by the hydrogen fuel cell reaction, and the water storage tank is sequentially connected to a filter, a water pump and a nozzle through a water pipe.

[0007] Preferably, a flow meter is provided on the water pipe.

[0008] A performance test method for a cooling system of a new energy commercial vehicle with spray evaporation, wherein a test environment is set, including air inlet temperature, liquid-temperature difference, coolant flow rate and wind speed. After the radiator sample reaches a thermal equilibrium stable state, the spray system starts to spray water, and the water spraying amount gradually increases from 0 at a rate of 0.1 L / min according to the heat exchange capacity of the radiator sample until water is observed on the air outlet side of the radiator sample, and then the performance test results are recorded.

[0009] Preferably, the inlet air temperature is 40℃~45℃, the liquid temperature difference is the difference between the hot side water inlet temperature and the cold side air inlet temperature, which is 40℃~45℃, the coolant flow rate is set to 2 to 4 values ​​according to the actual vehicle working point, and the wind speed is 2m / s~8m / s.

[0010] Preferably, the hot side medium in the radiator sample is ethylene glycol and pure water, wherein the volume proportion of ethylene glycol is 47% to 53%, the conductivity of the hot side medium is ≤20μS / cm, and the cold side medium is air at normal pressure.

[0011] Preferably, the air humidity on the windward side of the radiator sample is less than 50%, and the test environment is open.

[0012] Preferably, the nozzles of the spray system are arranged in a dot matrix according to the windward direction of the actual vehicle, so that the spray can cover the entire core surface of the radiator sample.

[0013] Preferably, the pressure difference on the windward side is measured by a pressure sensor.

[0014] Preferably, the inlet air temperature sensors are evenly arranged, and the outlet air temperature sensors are arranged every 1dm 2 One area layout.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. Under the premise of achieving the same heat exchange performance, the size of the radiator core is appropriately reduced to save fan power consumption, which saves more materials than traditional cooling modules;

[0017] 2. The increased heat dissipation comes from the product of the hydrogen fuel cell reaction - the evaporation of water absorbs heat, which does not consume additional energy and is environmentally friendly and pollution-free;

[0018] 3. Through performance test methods, provide data support for the design of vehicle thermal management system and optimize the design of heat exchanger products to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a cooling system for a new energy commercial vehicle with spray evaporation according to the present invention;

[0020] Figure 2 for Figure 1 Structural diagram of the spray system;

[0021] Figure 3 This is the water spray volume-evaporation latent heat characteristic table and characteristic curve for air side spraying.

[0022] The components in the figure are numbered as follows:

[0023] Radiator sample 1, sample installation panel 2, spray system 3, inlet air temperature sensor 4, outlet air temperature sensor 5, water storage tank 6, water pipe 7, filter 8, water pump 9, nozzle 10, flow meter 11. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 As shown, a new energy commercial vehicle cooling system with spray evaporation includes a sample installation panel 2 for installing a radiator sample 1, a spray system 3 is provided on the windward side of the sample installation panel 2, a plurality of air inlet temperature sensors 4 are provided on the outside of the spray system 3, and a plurality of air outlet temperature sensors 5 are provided on the air outlet side of the sample installation panel 2.

[0026] Among them, Figure 2 As shown, the spray system 3 includes a water storage tank 6 for collecting water generated by the hydrogen fuel cell reaction. The water storage tank 6 is connected to a filter 8, a water pump 9 and a nozzle 10 in sequence through a water pipe 7.

[0027] In addition, a flow meter 11 is provided on the water pipe 7 .

[0028] When the cooling system of a new energy commercial vehicle with spray evaporation is subjected to a performance test, the test environment is set, including the inlet air temperature, the liquid-to-air temperature difference, the coolant flow rate and the wind speed. After the radiator sample 1 reaches a thermal equilibrium stable state, the spray system 3 starts to spray water. The water spraying amount gradually increases from 0 at a rate of 0.1 L / min according to the heat exchange capacity of the radiator sample 1 until water is observed on the air outlet side of the radiator sample 1, and then the performance test results are recorded.

[0029] Specifically, the inlet air temperature is 40℃~45℃, the liquid temperature difference is the difference between the hot side inlet water temperature and the cold side inlet air temperature, which is 40℃~45℃, the coolant flow rate is set to 2~4 values ​​according to the actual vehicle working point, and the wind speed is 2m / s~8m / s.

[0030] Among them, the hot side medium in the radiator sample 1 is ethylene glycol and pure water, wherein the volume proportion of ethylene glycol is 47% to 53%, the conductivity of the hot side medium is ≤20μS / cm, the cold side medium is normal pressure air, and the air humidity on the windward side of the radiator sample 1 is less than 50%, ensuring that the environment during the radiator test is the same as the environment of the actual vehicle's working process, and it is an open test environment to prevent the air from being too saturated with moisture in a closed environment and affecting the evaporation effect of water vapor on the radiator surface. The nozzles 10 of the spray system 3 are arranged in a dot matrix manner according to the windward direction of the actual vehicle, so that the spray can cover the entire core surface of the radiator sample 1. In this embodiment, the spray distance is 30mm, the pressure difference on the windward side is measured by a pressure sensor, the inlet temperature sensors 4 are evenly arranged, and the outlet temperature sensors 5 are arranged every 1dm 2 One area layout.

[0031] The present invention utilizes the waste water generated by the hydrogen fuel cell, which is collected by the water storage tank 6 and then sprayed onto the surface of the radiator sample by the water pump 9, and utilizes the phase change after the liquid water evaporates and absorbs the heat of the air side surface of the radiator. This technology improves the heat exchange performance of the radiator by reducing the temperature of the air side surface of the radiator. Unlike the traditional single-phase airflow on the cooling air side of the radiator, after adding a spray device on the air inlet side of the radiator, the external flow field is transformed from a single-phase flow to a gas-liquid two-phase flow. Steady-state flow is used as the benchmark for testing and analysis. Therefore, when the spray technology is applied on the air side of the radiator, the model of the external flow field is a homogeneous flow model, that is, the gas and liquid phases have the same speed, and thermodynamic equilibrium is achieved between the gas and liquid phases.

[0032] The present invention relates to the following parameters:

[0033] The parameters describing the flow of single-phase fluids include velocity, mass flow rate and volume flow rate. In addition to these basic parameters, the mass content, volume content and velocity of each phase are also important parameters for gas-liquid two-phase flow. These basic parameters used to describe the flow field on the air side of the radiator are as follows:

[0034] W=W a +W l ……1.1

[0035] Where: W is the mass flow rate (kg / s), W a is the gas phase mass flow rate (kg / s), W l is the liquid mass flow rate (kg / s)

[0036]

[0037] Where: x is the mass gas content, 1-x is the mass liquid content

[0038] G=W / A……1.3

[0039] Where: G is the mass flow rate (kg / (m2*s), A is the front area of ​​the radiator core (m 2 )

[0040] Applying equations 1.2 and 1.3, we can know the relationship between mass flow rate and gas phase mass flow rate and liquid phase mass flow rate;

[0041] W a =GAx,W l =GA(1-x)…… 1.4

[0042] V=V a +V l …… 1.5

[0043]

[0044] Where: V is the volume flow rate (m 3 / s), V a is the gas phase volume flow rate (m 3 / s), V l is the liquid phase volume flow rate (m 3 / s), ρ a is the gas phase density (kg / m 3 ), ρ l is the liquid density (kg / m 3 )

[0045]

[0046] Where: J a is the gas phase converted velocity (m / s), J l is the liquid phase converted velocity (m / s)

[0047]

[0048] Where: m is the average density of gas-liquid two-phase flow-uniform flow (kg / m 3 ), μ m is the average velocity of gas-liquid two-phase flow - uniform flow (m / s)

[0049] After using evaporative spray technology, the heat transfer performance of the automobile radiator still follows the first law of thermodynamics, that is, the conservation of energy of heat absorption on the air side and heat dissipation on the liquid side. The calculation and analysis method of liquid side heat dissipation is the same as the traditional single-phase flow, but the air side includes two parts: the heat absorption on the gas side and the latent heat of evaporation of the spray water.

[0050] When the air side of the radiator is a gas-liquid two-phase flow, the heat dissipation on the liquid side of the automobile radiator is equal to the sum of the heat absorption on the air side of the radiator and the latent heat of vaporization of the spray water mist, that is:

[0051] Qw =Q a +Q r ……1.9

[0052] Q w =Cp w *m w *(T w1 -T w2 )……1.10

[0053] Q a =Cp a *m a *(T a2 -T a1 )……1.11

[0054] Q r =r*m s ……1.12

[0055] Where: Cp w is the specific heat of antifreeze (kJ / (kg·℃)), taken as 3.5kj / kg·℃, m w is the coolant mass flow rate (kg / s), T w1 is the radiator inlet coolant temperature (°C), T w2 is the coolant temperature at the radiator outlet (°C), Q w is the heat absorption of the radiator liquid side (kW), Cp a is the specific heat of cold air (kJ / (kg·℃)), m a is the mass flow rate of cold air (kg / s), T a2 is the radiator inlet air temperature (℃), T a1 is the radiator outlet temperature (℃), Q a is the heat absorption of the radiator on the wind side (kW), r is the latent heat of vaporization of liquid water (kJ / kg), m s is the water spray mass flow rate (kg / s), Q r is the latent heat of vaporization (kW).

[0056] Specific embodiments are listed below:

[0057] The test sample is a radiator for a new energy commercial vehicle using hydrogen as the main fuel. It is required to be a qualified product that has passed the on-site quality inspection, and there should be no dust, oil or other impurities in the installation area of ​​the test sample. The specific test environment is as follows:

[0058] (1) Inlet air temperature (℃): 41

[0059] (2) Liquid temperature difference (℃): 44

[0060] (3) Coolant flow rate (L / min): 100, 150, 200, 250

[0061] (4) Frontal wind speed (m / s) 2, 4, 5, 6, 7

[0062] (5) Water spray volume (L / min): 0.0~2.0

[0063] (6) Sample size (mm): 808*1050*42, core front area 0.852m 2

[0064] The calculation of the fuel cell radiator performance test parameters is based on gas-liquid two-phase flow, thermodynamic equilibrium theory and water evaporation latent heat theory. Combined with the test conditions, a coolant flow rate of 100L / min is taken to obtain detailed description parameters of the flow field under different wind speeds, see Tables 1 to 5. After analyzing the calculation data, the following conclusions can be drawn:

[0065] During the radiator evaporation spray test, if the condenser is not installed, the heat dissipation on the liquid side of the radiator is relatively independent and is only directly affected by the coolant mass flow rate, the inlet and outlet water temperature difference and the coolant specific heat;

[0066] Since the mass of water sprayed on the air side of the radiator is very small, the gas-liquid two-phase flow characteristics on the cold air side of the radiator are dominated by gas phase flow in terms of mass and volume parameters. The mass liquid content and volume liquid content of the liquid phase flow calculated based on the water spraying amount are both less than 1%. Compared with the mass liquid content, the volume liquid content is smaller. The main reason for this difference is the difference in order of magnitude between water density and air density.

[0067] Table 1 Gas-liquid two-phase flow characteristics when the wind speed is 2m / s and the water spray volume is 0-0.2L / min

[0068]

[0069] Table 2 Gas-liquid two-phase flow characteristics when the wind speed is 4m / s and the water spray volume is 0-0.2L / min

[0070]

[0071] Table 3 Gas-liquid two-phase flow characteristics when the wind speed is 5 m / s and the water spray volume is 0-0.2 L / min

[0072]

[0073] Table 4 Gas-liquid two-phase flow characteristics when the wind speed is 6 m / s and the water spray volume is 0-0.2 L / min

[0074]

[0075] Table 5 Gas-liquid two-phase flow characteristics when the wind speed is 7m / s and the water spray volume is 0-0.2L / min

[0076]

[0077] In this embodiment, the radiator performance test using the spray evaporation technology still follows the first law of thermodynamics:

[0078] Q w =Q a +Q r ……3.1

[0079] Taking the vaporization latent heat as 2257kJ / kg and calculating according to the above formula, the thermal balance errors on the air side and the coolant side are consistent. The thermal balance errors of most test points are within ±5%. The thermal balance errors of very few test points exceed ±5%. These points are distributed in the working range with small water spray volume, small cold air mass flow rate, and small liquid side coolant flow rate. The main reason for this phenomenon is that the absolute value of the heat transfer power is small. In addition, if Figure 3 The water spraying amount-evaporation latent heat characteristic table and characteristic curve of air side spraying can be directly applied to the test data processing process.

[0080] The cooling system of the new energy commercial vehicle with spray evaporation of the present invention and the performance test method thereof, under the premise of exerting the same heat exchange performance, appropriately reduce the size of the radiator core, save fan power consumption, and save more materials than the traditional cooling module; the increased heat dissipation comes from the evaporation heat absorption of the product of the hydrogen fuel cell reaction - water, which does not consume additional energy and is environmentally friendly and pollution-free; through the performance test method, data support is provided for the design of the thermal management system of the whole vehicle, and the design of the heat exchanger product is optimized to the greatest extent.

Claims

1. A cooling system for a new energy commercial vehicle with spray evaporation, comprising a sample mounting panel (2) for mounting a radiator sample (1), characterized in that: A spray system (3) is provided on the windward side of the sample installation panel (2), a plurality of air inlet temperature sensors (4) are provided on the outside of the spray system (3), and a plurality of air outlet temperature sensors (5) are provided on the air outlet side of the sample installation panel (2).

2. The new energy commercial vehicle cooling system with spray evaporation according to claim 1 is characterized in that: The spray system (3) comprises a water storage tank (6) for collecting water generated by a hydrogen fuel cell reaction, wherein the water storage tank (6) is sequentially connected to a filter (8), a water pump (9) and a nozzle (10) via a water pipe (7).

3. The cooling system for new energy commercial vehicles with spray evaporation according to claim 2 is characterized in that: The water pipe (7) is provided with a flow meter (11).

4. A performance test method for a new energy commercial vehicle cooling system with spray evaporation as claimed in any one of claims 1 to 3, characterized in that: The test environment is set up, including the inlet air temperature, the liquid temperature difference, the coolant flow rate and the wind speed. After the radiator sample (1) reaches a thermal equilibrium stable state, the spray system (3) starts to spray water. The water spraying amount is gradually increased from 0 at a rate of 0.1L / min according to the heat exchange capacity of the radiator sample (1) until water is observed on the air outlet side of the radiator sample (1), and then the performance test results are recorded.

5. The performance test method of the cooling system of a new energy commercial vehicle with spray evaporation according to claim 4 is characterized in that: The inlet air temperature is 40℃~45℃, the liquid temperature difference is the difference between the hot side inlet water temperature and the cold side inlet air temperature, which is 40℃~45℃, the coolant flow rate is set to 2~4 values ​​according to the actual vehicle working point, and the wind speed is 2m / s~8m / s.

6. The performance test method of the cooling system of a new energy commercial vehicle with spray evaporation according to claim 4 is characterized in that: The hot side medium in the radiator sample (1) is ethylene glycol and pure water, wherein the volume proportion of ethylene glycol is 47% to 53%, the conductivity of the hot side medium is ≤20μS / cm, and the cold side medium is normal pressure air.

7. The performance test method of the cooling system of a new energy commercial vehicle with spray evaporation according to claim 4 is characterized in that: The air humidity on the windward side of the radiator sample (1) is less than 50%, and the test environment is open.

8. The performance test method of the cooling system of a new energy commercial vehicle with spray evaporation according to claim 4 is characterized in that: The nozzles (10) of the spray system (3) are arranged in a dot matrix according to the windward direction of the actual vehicle, so that the spray can cover the entire core surface of the radiator sample (1).

9. The performance test method of the cooling system of a new energy commercial vehicle with spray evaporation according to claim 4 is characterized in that: The pressure difference on the windward side is measured by a pressure sensor.

10. The performance test method of the cooling system of a new energy commercial vehicle with spray evaporation according to claim 4 is characterized in that: The inlet air temperature sensors (4) are evenly arranged, and the outlet air temperature sensors (5) are arranged every 1dm 2 One area layout.

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