Numerical Simulation Of The Jet Flow Characteristics Of The Round Personalized Vent

At present, people are more inclined to quick and comfortable ways to travel. Thus, large airliners are becoming more and more popular. The air environment quality inside the cabin becomes the main indicators of quality assessment of flight comfort under high-altitude environment. It also becomes an important topic of modern cabin comfort research. The airflow distribution inside the airline cabin is the key issue to study environmental control inside airline cabin.There are a great quantity of personalized vents and fissure type vents inside the airline cabin. The coupling of multiple flows makes the air distribution inside airline cabin complicated and changeable. Thus, the accurate simulation of air flow inside airline cabin becomes very difficult. It is crucial to develop an appropriate and efficient model for the simulation of turbulent flow inside the airline cabin.In order to establish efficient, reasonable and accurate simulation method which is suitable for air flow simulation inside the cabin environment, personalized air supply opening jet flow that based on aircraft personalized vents is simplified to round jet flow. Then numerical simulations and analysis are carried out for round turbulent jet. The conclusion that the simulation using standard ?-? turbulence model with dense grids is in good agreement with the results of classic experiment is verified. On the basis of all, it analyses the dependencies between the field of round turbulent jet and the velocity profile of jet outlet. Also the influence of crosswind to the characteristics of jet flow is studied.Starting with the comparison of experimental results with the results of numerical simulation, where the standard ?-? turbulence model with fine gird was used, the analysis of the simulation results with coarse grids revealed that an increase in gird scale causes a significant decline of velocity in jet flow along the axial and radial directions. From the view of turbulent dissipation rate equations, this excessive decay of jet flow with coarse grids is resolved by modifying the turbulent dissipation rate of the generation and dissipation terms to balance the factors that cause an excessive decay. The modified dissipation rate ?-? turbulent model is presented in this paper. The applicability of the modified model under different Reynolds numbers and non-isothermal conditions is also studied. The results show that the new model is able to significantly reduce the total number of grids as well as to achieve the correct field characteristics of personalized vents jet flow. The modified turbulence model is found to be capable of solving the grid requirements for the simulation of flows in aircraft cabins. The flow characteristics inside the cabin with complex structures and boundary conditions can be accurately and rapidly simulated as well. It laid the foundation of fast and accurate numerical simulation in the whole airline cabin.