Natural Convection Heat Transfer Study And Thermal Analysis Within An Aircraft Complex Enclosed Space

Natural convection is an essential method of heat transfer which happens inside theenormous aeroplanes. Nowadays as the electronic widgets with high power are widely usedin the electronic systems equipped in the aeroplane, the influence of natural convection inthe formation and characteristics of the temperature field is growing more and moreobvious. Considering that the system in the aeroplane is required to be adaptive to differentconditions which are under different temperature, in order to make all the devices worknormally, the temperature inside the aeroplane needs to be controlled to a steady level.Owing to the limitation of computational resources in the current thermal analysis ofenormous aeroplane, the experimental relevant equations is usually adopted to solve theconvective problem, however, the inaccuracy is not as little as the ideal situation. As for theCFD softwares, though it has great superior in solving the problems of fluid flow and heattransfer, the efficiency is very low when the CFD softwares is applied in theconduction-convection-radiation integrated heat transfer problem under the effect ofmulti-systems, unsteadiness and dispersive heat source. In some featured situations theCFD softwares are not even available to carry out the simulations. This paper has taken thethermal analysis of enormous aeroplane as research background, by analyzing the heattransfer processes inside closed spaces with different conditions and structures, theproblems of conduction-convection-radiation integrated heat transfer in complicated closedspaces with different thermal verge conditions is solved. The main contents of our research(1) Comparing the influences of experimental relevant equations and accurate CFDsimulation results in temperature field. Under the same solving condition, the numericalsimulation of closed space with multi-systems, dispersive heat sources is calculated byusing the commercial CFD software of Fluent and software of SINDA/FLUINT based onthermal net method.(2) As for the conduction-convection-radiation integrated heat transfer problems existin the multi-systems, by further extracting the software of Fluent and SINDA/FLUINT, theanalysis which united the thermal net method and CFD solution to solve the multi-systemintegrated transient heat transfer problem, the influence of huge space inside the aeroplaneand large amount of calculation was also taken into consideration, then the influences ofnatural convective coefficients under3-D conditions and simplified2-D conditions in simulation of temperature field is analyzed.(3) For the complex closed space inside this specific kind of aeroplane, thedemonstrative model was combined with the information about quality and material of thedevices, the geometric model was established by the software of CAD and CATIA. Thesoftware of Fluent and SINDA/FLUINT were coordinated to calculate and analysis theproblems of conduction-convection-radiation integrated heat transfer in complicated closedspaces, furthermore, the differences between the situations that the convective coefficientsare modified and not modified was compared, the influence of different thermal vergeconditions was also analyzed.Through the research in this paper, we have provided some designing referencesinvolving the process of natural convection and have obtained some useful solving methodsand some valuable conclusions.