近年来，随着科技发展和生活水平提高，活体动物的运输量越来越大。特种运输车辆增设通风空调系统可改善运输过程中活体动物的生存环境。但国内现有活体运输车中普遍存在气流组织不合理的问题，导致车厢内局部气温过高或过低，动物存活率低、车辆装载量少。该文以兔子运输车为例，利用 CFD 软件模拟分析了现有车厢内空气流动和传热状况，并提出风口优化布置原则：将回、排风口置于高温区域，提高回、排风温度。研究表明，现有车厢内气流短路现象严重，车内最高温度超出设计温度范围3.20℃，且约21%的兔笼超温；优化布置的风口可明显改善车厢内空气温度分布；所有兔笼温度均保持21.05～29.20℃以内，满足设计要求。该工作对活体动物运输车的设计和生产具有指导意义。%With the development of technology and the improvement of life standard, the poultry and rabbit breeding industry becomes prosperous and the transportation volume of live animal is larger and larger. To improve the living environment of animal during transportation, the special truck equipped with air conditioner is developed. However, the unreasonable air distribution is a universal problem in the body of this specific truck, leading to local air temperature too high or too low which causes the low animal survival rate and low vehicle loading capacity. There were some simulations and experiments on the refrigerator car, but few on the animal truck. With the requirement of the market, a truck carrying rabbits is chosen as the research object, which is produced by Kangfei Mobile Systems Company in Jiangsu Province. There are 98 air inlets with the radius of 25 mm installed uniformly on the roof of the truck body, 2 air returning outlets with the radius of 160 mm on the front wall of the truck body and 5 air exhausting outlets with the radius of 60 mm on each side of the truck body. This truck carries 1 170 adult rabbits with the designed inside temperature of 18-30 . How to calculate the flow field and temperat℃ ure field of the existing truck and how to optimize the vent layout to achieve a homogeneous temperature distribution of the truck body are the main work in this research. The air flow and heat transfer condition in the truck body are simulated by the Airpak 3.0, which is used for air flow simulation and developed by the ANSYS. The simulation uses 2 equations to calculate the turbulence flow characteristics. The control equations are the standard k-ε equation, the quality equation and the energy equation. The finite volume method (FVM) is used as the discrete method, the one order difference format is used as the wind difference scheme, and the SIMPLE algorithm is used for iterative computation. The simulation method turns out to be accurate through verification by experiment, with the error of less than 3.5% between the simulated and the test results. The research shows that the short circuit of air flow in the front is a serious problem of the existing truck, causing that most supplying air in the upper front of the truck is exhausted directly through the front outlets at low temperature and thereby the utilization of the cool air is not enough. Influenced by the flow field, the air temperature in the truck is low at the upper front part and high at the lower front part with the large temperature difference of about 15.20 between them. The highest℃temperature in the truck body exceeds 3.20 compared with the design temperature range and nearly 21% of rabbit cages℃suffer from the high air temperature. To solve this problem, the principle of vent layout is proposed, which is setting the exhausting and returning outlets at the high temperature area to improve the utilization of the cool supplying air as soon as possible. The optimal vent layout of the rabbit truck is keeping inlets at the roof, and placing outlets at the lower part of both side and bottom of the truck. After the optimization, the air supplied from the inlets flows a longer distance and is mixed more adequately with the air inside, solving the previous short circuit problem of the flowing. The air temperature distribution in the truck body is investigated to be more homogeneous and the maximum temperature difference is decreased to 12.18 ℃. The air temperature of all the rabbit cages keeps in 21.05-29.20 ℃, satisfying the design well. This work investigates the air flow and temperature distribution of the existing truck, proposes the principle of optimal vent layout and simulates the air temperature distribution of the truck after optimization, and the results are significant for the design and production of the truck carrying rabbits.
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