Modeling Hydrogen combustion in a hypersonic flow using Ansys CFX

Аuthors

Platonov I. M.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: platonov@mai.ru

Abstract

While designing and constructing new aircrafts and space-rockets sometimes it is useful to perform a preliminary modeling of the design as applied to future exploitation conditions. This measure allows the designer to spot problem areas in the structure and flaws in organization of working process early in project development cycle.

In this document the problem of estimation the effectiveness of different type of fuel injection is considered. To solve stated problem a mathematical model is put together, including Navier-Stockes equations, chemical kinetics and turbulent model. In chemical kinetics the reactions of hydrogen combustion and air dissociation are taken into account. Hydrogen combustion is described by seven elemental reaction equations. Air dissociation described by five equations. This amount of equations allows for 80% of total impact on flow by chemical transformations, which is enough for a preliminary calculation. The chosen turbulent model is SST — Menter turbulent model, because it describes both freestream and near wall flows sufficiently enough. To solve the problem via numerical methods a tetra-mesh of 500 thousand elements was built. Computations were performed in quasi-stationary mode.

Verification of the mathematical model was performed using data from experiments conducted in the Institute of Theoretical and Practical Mechanics combustion laboratory, Siberian Branch, by P.K. Tret’yakov. The combustible used in experiments was hydrogen. Studies were conducted for adjacent and supersonic hydrogen injection into a scram-jet. The experiment facility was a profiled supersonic nozzle, from which hot air was dispensed. On the symmetry axis a pylon was mounted, thru which hydrogen came into the flow.

Some results of numerical simulation of supersonic combustion were given in this article. They correlate with experimental data fairly well. Based on these results it is possible to perform a numerical simulation of supersonic combustion in a scram-jet engine using the proposed mathematical model.

Keywords:

hypersonic flow, Navier-Stokes equations, equations of chemical kinetics, Hydrogen combustion

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