Optimal Study On Airflow In Air Supply Channel And Airflow Inside Passenger Cabin Of Air Conditioning Subway

With the development of railway construction in China and the improvement of living standard, people set a higher thermal comfort. The air-conditioning ventilation system in the metro car is designed mainly according to the design standard of air-conditioning ventilation system in the railway car without design experience, therefore, we need put forward a designing approach to this system based on the characteristics of the operation and the work environment itself.The air-conditioning ventilation system of a metro continued project was studied by the numerical calculation method in the thesis. The air flow inside the duct ,the temperature and flow field in the subway air-conditioning compartment was simulated by computational fluid dynamics and the professional software, which adopts the standard 3D incompressible k-εtwo-equation turbulence model which modifies the item of buoyant effect and SIMPLE algorithm.First, the air flow in the duct and ventilating uniformity via air supply channel was studied by numerical simulation with experiment investigation. Turbulent flow field in the duct was simulated and analyzed by comparison the computational results with the experimental ones,and the numerical calculation was validated by the experiment result. The internal structure of the duct was adjusted based on the theoretical research result, and the influence on the supply air uniformity was predicted, then, the structure of the duct was optimized above analysis.Three different air distribution methods were simulated in the passenger compartment. And the best air distribution method was obtained for this kind of car. In the calculation, many kinds of heat transfer was taken into account such as the heat transfer of walls and the heat transfer radiating from human body, and so on. The numerical stimulation result was post-processed by software TECPLOT, and the distribution characteristics of the temperature field and velocity vector field is analyzed in order to obtain the flow distribution rules. By comparing the advantages and disadvantages of the different air distribution methods, theoretical basis for optimization air distribution design is provided. The result shows that upper air supply, upper air return and middle air exhaust is an optimal air distribution method. This research proves that it is feasible to analyze and optimize the air distribution of the air duct and the passenger car by using the numerical analysis method. The conclusions offer some guide for the future design of air-conditioning ventilation system for the metro car.