Numerical Simulation And Experimental Study Of Flow&Heat Transfer And Thermal Comfort Performance Of A Training-Plane's Air-Conditioning Cockpit

For evaluating the performance of ECS (Environmental control system) of a training-plane and thus improving its design, numerical simulation and experimental study is carried out of flow and thermal fields within a training-plane's air-conditioning cockpit.Firstly, the geometrical model of the cockpit is established. According to the freeform surface feature of the cockpit surface, the construction method and procedure of the cockpit surface used NURBS (Non-uniform rational B-spline) surface, and the mesh generation method for the NURBS surfaces are given, and a3-D unstructured mesh are generated for the cockpit.For improving the numerical accuracy of human thermal comfort performance, an improved algorithm for the computation of PMV (Predicted mean vote) is proposed, in which the convective heat transfer coefficient on the human's body surface is obtained by solving the control equations directly, not by just using a conventional empirical correlation. According the layout features of the ECS, the models of boundary conditions for the inlets in the inner part of the cockpit are proposed for the convenience of numerical simulation, such as 'inlet bend' model and 'mass and momentum flux source' model. The models for the boundary condition treatment can provide a clue for other physical problems with inner inlet boundaries.The numerical results show that the flow in the cockpit can take the heat from the pilot effectively on whole, however, the heat dissipation of the pilot in the back cockpit is a little weaker than the one in the front cockpit due to the weaker flow around his head. PMV index increases with increasing inlet air temperature, metabolism rate and thermal resistance of cloths, and PMV shows a linear relationship with temperature. With the increase of metabolism rate, the effect of cloths'thermal resistance increases obviously. With the decrease of humidity in the cockpit, PMV decreases. Compared with a high humidity case, a higher inlet temperature is required for a low humidity case.The numerical results can provide guidance on design and optimization of air flow in the cockpit to control human thermal comfort for different thermal environments. The theories and algorithm for the study of flow and thermal comfort in the cockpit can lay the foundation of numerical simulation of flow and heat transfer within a limited arbitrary space.By setting up experiment platform and applying numerical simulation and calculation results, in this paper the study of designing plan and experimental validation of the system of environment-control and demisting within a certain kind of traing plane is also made.