МОДЕЛИРОВАНИЕ ПРОЦЕССОВ ТЕПЛООБМЕНА ВНУТРИ ГЕРМЕТИЧНОГО КОРПУСА БИНС В МУЛЬТИФИЗИЧНОЙ ПОСТАНОВКЕ В ANSYS CFX И SYSTEM COUPLING

Abstract

The article presents a numerical simulation of non-stationary convective-conductive heattransfer of the strapdown inertial navigation system (SINS), developed in the JSC «CNIIAG».The numerical simulation is carried out in the ANSYS Mechanical. The aim of the study is a comprehensiveanalysis of heat exchange processes, which are characteristic to the device operation,including mutual spatial influence of thermal powers on each other, as well as on the block ofsensitive elements. The simulation of heat transfer inside the hermetic case of the SINS is carried out for critical operating conditions in a strongly and weakly coupled consideration with a comparisonof both approaches. ANSYS Mechanical, CFX and System Coupling simulation modulesare chosen for program implementation of each approach. The k-e model of air turbulence withimplicit consideration of the effect in the boundary layers and diffusion correction in shear flows ischosen for this approach. External heat exchange with ambient air is considered by setting convectiveboundary conditions on the external surfaces of the SINS, considering their orientation.To obtain numerical values of the heat transfer coefficients, the orientation of each surface inspace is taken into account by using the appropriate coefficient. The presence of irregularities onthe surfaces of the SINS in the contacts between solid components is considered by using the calculationof thermal resistances of the actual contact and intercontact layer. The simulation resultsof deformed state of SINS structural system, resulting from the action of a non-symmetric thermalfield, is presented. The analysis of the obtained graphs is carried out. Stiffness indicators of theSINS structural system is defined as angles of deviation of sensitivity axes caused by thermal deformations.The obtained results make it possible to evaluate the engineering solutions for thequality of heat removal from the elements of the PCBs, bypassing the sensitive elements of thedevice, adopted at the stage of product layout.