THE CAPABILITIES OF OPEN SOURCE CFD CODE FOR MODELING THE STAND TANK FILLING PROCESS WITH LIQUID HYDROGEN

Abstract

The paper analyzes the functioning and launching of the cryogenic propulsion upper stages and the stages of rocket-space systems, which are largely determined by heat and mass exchange processes in the elements of supply systems. This is due to the fact that in ground conditions, there are no possibilities of flight conditions simulation during cooling of feed lines and starting the engine. Therefore, the simulation of the flow of cryogenic components with respect to heat and mass exchange processes in supply systems of the units and the test stand is important. The paper gives data that booster pump aggregates of oxidant and fuel, as a rule, are located in the corresponding fuel tanks. This makes it possible to significantly reduce the costs of the component for carrying out the operations of cooling and filling fuel lines and the tank, and to optimize the process of starting the engine when it is switched on repeatedly. It is also noted that in complex ground tests of upper stages there are usually no possibilities to simulate flight conditions during launching operations in complex ground tests of upper stages, therefore the use of physical and mathematical models for the calculation of nonstationary multiphase processes with intensive phase transformations makes it possible to determine the characteristics and to forecast the parameters of supply systems. The following tasks have been accomplished: the development of open source code based on CFD program OpenFoam for simulation of cryogenic flows in conjunction with heat exchange processes with the wall of the tank; the verification of open source code on a simple two-dimensional model of the tank for determination the main mechanisms that arise in the process of cooling and filling the stand tank; the implementation of open source code for simulation the initial stage of the refilling of the stand fuel tank taking into account the evaporation of the cryogenic liquid and heat exchange with the walls. The paper shows that the processes of flow and evaporation can be modeled in the framework of models with a free surface flow. The results of calculations of basic parameters of two-phase flows in the process of cooling the liquid hydrogen fuel tank are presented. The results of the study are expected to be used in the methodology for estimating the parameters of two-phase flows during testing of the advanced space rocket systems.