Ventilation Simulation and Uniformity Optimization of Air Supply for Double-deck Passenger Cars

doi:10.3901/JME.2020.14.129

Abstract

Abstract: Aiming at the issue of the uniformity of air supply in the passenger compartment of a double-deck passenger car, a numerical calculation model for double-deck passenger car air duct and passenger room ventilation is established, and the airflow uniformity of the air duct and the wind speed inside the vehicle are analyzed. According to the relevant comfort evaluation index in ASHRAE 23, the velocity field in the passenger compartment is evaluated and optimized based on the numerical results. The result shows that the air duct with a constant cross-section cannot satisfy the uniform requirement for air supply, the airflow volume in the beginning of the air duct is small, whereas the air volume in the end is large, and the outflow of the inner outlet has a large longitudinal velocity, which causes the airflow gathering along the downstream of the air duct. The pressure loss at the right corner is large, and the rounded transition can effectively reduce the local flow resistance with an amplitude of 40%. The static pressure chamber at the air outlet is relative small, which can not effectively reduce the jet impact at the internal tuyere. Lateral rectification measures to reduce the longitudinal velocity of the airflow. Meanwhile, measures such as increasing the lateral rectifying plate, the deflector, the resistance plate, and the triangular baffle can effectively adjust the uniformity of the airflow along the longitudinal direction of the air duct. In the case of keeping the original air duct installation space and shape, the combined optimization measures ensures the uniformity of the air supply to satisfy the standard requirements.

Key words: double-deck passenger car, internal flow field, air supply uniformity, numerical simulation, duct optimization

CLC Number:

U266

CAI Lu, ZHANG Jiye, LI Tian. Ventilation Simulation and Uniformity Optimization of Air Supply for Double-deck Passenger Cars[J]. Journal of Mechanical Engineering, 2020, 56(14): 129-137.

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