Inverse Determination Of Thermal Boundary Conditions On The Inner Wall Of Aircraft Cabin During Cruise

When the aircraft cruises at high altitude,the external environment of the cabin is extremely bad,and the impact of the external environment on the cabin environment cannot be ignored.In order to create a comfortable cabin environment,it is very important to accurately determine the thermal boundary conditions of the cabin inner wall.However,the traditional method to determine the thermal boundary is to continuously guess and iterate through a series of lengthy and complex calculations,which not only consumes hashrate,resource efficiency is very low,but also difficult to solve.However,there is no fast and accurate method.In order to solve this kind of problem,in this study,considers the couple of the ambient environment and the cabin environment,an inverse modeling using Computational Fluid Dynamics(CFD)combined with Green’s function and regularization method is proposed to solve the convective heat transfer of inner wall by using the air temperature at monitored points in the cabin.The inverse model proposed in this paper is based on computational fluid dynamics(CFD),combined with Green’s function and regularization to solve the convective heat transfer on the inner wall of the cabin under the coupling of internal and external environment during aircraft cruise.In the steady flow field,the Green’s transfer matrix is established through the known temperature of discrete measuring points in the cabin space.Due to the ill-posed nature of the inverse problem,regularization methods are used to ensure the stability of the inversion solution.This investigation compares the performance of Tikhonov,truncated singular value decomposition(TSVD)and damped generalized singular value decomposition(DGSVD).They are solved inversely to determine the boundary convective heat transfer on the inner wall of the cabin,and the method with the highest accuracy is obtained.Because the Green’s transfer matrix is used to describe the causal relationship between the temperature of the monitoring point and the thermal boundary,it is separated from the Navier-Stokes equation for solution,which greatly improves the calculation efficiency of the model and reduces the difficulty of calculation.In this paper,the actual test is carried out on the small-scale cabin test-bed.The external environment of aircraft cruise altitude is simulated by using the high and low temperature damp heat low pressure box,and the flow and thermal characteristics in the cabin are restored.Based on the measured data,the practical feasibility of the inverse model proposed in this paper is verified,furthermore,the CFD model of conjugate heat transfer(CHT)in three-dimensional cabin with actual size is established.The feasibility of the inverse model is verified again with the simulation data,and the three regularization methods are compared and optimized.The results show that the proposed inverse model can accurately and efficiently solve the convective heat transfer at the boundary of the cabin inner wall under the coupling condition of internal and external environment,and the Tikhonov regularization method has best solution accuracy.