Turbulence Characteristics Analysis Of Jet Flow And Application Investigation For Numerical Simulation Strategy In Aircraft Cabin

At present, airplane increasingly becomes an essential tool for passenger to travelas its high-speed and comfort property. Thus the environment quality in aircraft cabinis even more important. The high effective and accurate simulation for the air flowdistribution in cabin will help to significantly understand and control the diffusion ofthe pollutants and particles in the cabin.In the cabin environment, jet exit of air-condition vents and the surface of humanbody or the seats has a great influence on the cabin air organization and human body’scomfort. This jet flow belongs to the category of free jet and impinging jet flow. Thenumerical simulation method was used to calculate and obtain the flow information.The Reynold stresses were analyzed and fitted as a function. Then it applied to N-Sflow equations as a source term of body force to numerically solve the flow field.Firstly, the simulation of lower Re number impinging jet with temperaturedifference and free jet was calculated by the N-S equation and the turbulence modeland compared to experiment data. The heat transfer characteristics and distribution ofthe turbulent Reynolds stress were also analyzed. The Rational Taylor model wastested to fit the Reynolds stress as a representation function of turbulencecharacteristics of jet flow. The fitted Reynolds stress function was used as sourceterms of body force to participate the numerical calculation of control equations of jetflow. Then the result was compared to that of turbulent model under same boundaryand flow conditions to verify the source items.The calculation and analysis results show that at lower Re number impinging jetwith temperature difference, the surface Nusselt number is high near the jet coreregion and gradually decreases away from the jet core. In impact plate surface, as aresult of the existence of temperature difference caused by the thermal buoyancy, thecoefficient of thermal conductivity is obviously affected by air temperature and walltemperature. Appropriate thermal conductivity coefficient can improve the numericalresults. For the free jet simulation, the Reynolds stress is also highest near the jet coreregion and gradually decreases away from the jet core. Three different types of fittingmethod were applied to fit Reynolds stress. It was found that there exists a certaindeviation between them and the deviation has an influence on the calculation results. This is reflected in the jet attenuation and diffusion respectively. Compared thedifferent inlet Reynolds number calculation results, It was found that thedimensionless Reynolds stress distribution and order of magnitude are basically thesame. Within the scope of the inspection, the grid number does not affect thecalculation results. This shows that the calculation method of body force source termapplied to the flow control equations is feasible.