Research on the influence of fin design and air side flow characteristics of automobile evaporator on heat exchange efficiency and air outlet temperature

The fin design and air side flow characteristics of the automobile evaporator are the core factors that determine its heat transfer efficiency and air outlet temperature, which have an important impact on the overall performance of the automobile air conditioner.The main function of the evaporator fins is to increase the heat transfer area and promote the heat transfer between the air and the refrigerant.Common fin forms include straight fins, corrugated fins and blinded fins, each with its own characteristics and applicable occasions.The straight fins have a simple structure and small air resistance, but the heat transfer coefficient is low; the corrugated fins improve the heat transfer efficiency by increasing the degree of disturbance of air flow; the blinded fins punch out many tiny openings on the fins, further destroying the air boundary layer and significantly enhancing the heat transfer effect. It is currently a widely used form of high-efficiency fins.

The design of fin density and spacing needs to consider the balance between heat transfer efficiency and air resistance.If the fin spacing is too small, although the heat transfer area is increased, the air flow resistance increases and the power consumption of the fan increases, which may lead to insufficient air volume through the evaporator; if the fin spacing is too large, the heat transfer area is reduced and the heat transfer effect decreases.Therefore, according to the specific requirements of the air conditioning system, the optimal fin parameters need to be determined through theoretical calculations and experimental verification.In addition, the hydrophilic treatment of the fin surface is also an important feature of modern evaporator design. The hydrophilic coating enables the condensate to spread out and flow down quickly, avoiding the formation of water bridges that hinder air flow and maintain the long-term efficient operation of the evaporator.

The air-side flow characteristics are not only related to the fin design, but also affected by the overall size and installation method of the evaporator.The speed distribution of air when it flows through the evaporator should be as uniform as possible to avoid uneven heat transfer caused by local wind speeds that are too high or too low.If the wind speed is unevenly distributed, some areas may be frosted due to the low wind speed, and some areas may have insufficient heat transfer due to the high wind speed, which affects the overall cooling effect and the stability of the air outlet temperature.Therefore, the installation location of the evaporator in the air-conditioning box and the design of the air inlet also need to be optimized to ensure that the air flow can pass evenly through the surface of the evaporator core, give full play to its heat transfer capacity, and provide a comfortable air flow with stable temperature and uniform distribution in the car.