Numerical Simulation Of HVAC And The Blowing Face Duct In Vehicle Air Conditioning System

In the increasingly fierce competition in the automotive industry, vehicle air conditioning is more and more prominent for the comfort of the vehicle and has become one of the principal means of market competition. Therefore, how to improve the structure of vehicle air conditioning systems, reducing aerodynamic noise and the vortex phenomena in HVAC and duct, improving the heat transfer of the evaporator core and heater core. With the rapid development of the computational fluid dynamics, CFD software can be relatively fast, accurate and intuitive reflect the air flow in air conditioning system, it is very easy to find the problem in the design through the analysis of flow field, using CFD technology to design vehicle air conditioning has become an important method. So, to carry out numerical simulation for air flow in vehicle conditioning system, it has important practical value for the design, development and improvement of vehicle air conditioning system. In this paper, using the numerical simulation method to study in the air flow in HVAC and the blowing face duct, in order to find the optimal design theory basis for HVAC and the blowing face duct. The main contents are as follows:This paper was first to establish HVAC simplified three-dimensional geometric model, according to the structural characteristics of the model, using different grid types of discrete regions of space, the evaporator core and heater core was simplified porous, using commercial software FLUENT to numerical simulate HVAC, the characteristics of the flow field and sound field were analyzed and summarized, analyzing the unreasonable structure of HVAC. The results show that vortex phenomena in HVAC are likely to cause noise, heat transfer efficiency was affected by the surface velocity of evaporator core and heater core.Then, the irrational structure of HVAC model was improved, for the problem of vortex phenomenon in HVAC and the low efficiency of evaporator core, increasing the guide vane before the evaporator core. The numerical simulation results shows that the vortex phenomenon has improved, the surface velocity of evaporator is more balanced and the heat transfer efficiency of evaporator core has improved.Finally, to simulate the real situation of the inlet of the blowing face duct, considering the effect on outlet flow and velocity by inlet velocity was uneven, numerical simulating the HVAC and the blowing face duct together. Through analyzing the flow field and sound field of the blowing face duct, getting the internal structure effect on the duct air distribution, velocity and aerodynamic noise. Proposing the improvement scheme by the result of numerical simulation. After improvement, air flow distribution and velocity are more balanced in the blowing face duct, reducing the aerodynamic noise, improving the overall performance of air conditioning.