Optimization of air supply mode of vehicle air conditioning based on digital thermal manikin

With the rapid development of the automobile industry, the public's demand for automobile diversification is growing steadily.People are no longer satisfied with basic driving convenience, more attention is now directed to the thermal comfort of the cabin. In order to build the relationship between in-vehicle environment parameters and thermal comfort index, the concept of equivalent temperature (Teq) was introduced, and then the DTM reflecting the thermal comfort of the human body was applied to the simulation of ANSYS Fluent. For a specific working condition of the vehicle air conditioning, the equivalent temperature of the in-vehicle environment was tested by the DTM, and it was found that the highest Teq (approximately 27°C) was observed in the foot region of the passenger. The Teq of most areas of the passenger's body was relatively low, especially in the temperature sensitive torso, it was about 15-20°C. Numerical calculations for the same working conditions were carried out using the DTM. By comparing the results of Teq between the DTM and the physical thermal manikin, it was found that the results are very similar, the Teq deviation was less than 3℃, indicating that DTM can be used to measure Teq instead of physical thermal manikin. Finally, the DTM model was used to optimize the air outlet of the vehicle air conditioning system. The results showed that the best comfort was achieved when the air velocity was 4 m/s, the outlet temperature was 25℃, and the airflow was directed toward the occupant's abdomen.This study demonstrates that DTM can replace physical experiments in thermal comfort evaluation, providing an efficient and low-cost approach for optimizing vehicle HVAC design.