Mathematical Simulation of Heat Transfer and Chemical Reactions in an Equilibrium Dissociating Gas

• Published in: Journal of engineering physics and thermophysics Vol. 94; no. 2; pp. 437 - 449
• Main Authors: Matvienko, O. V., Martynov, P. S.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-03-2021; Springer; Springer Nature B.V
• Subjects: Chemical reactions; Classical Mechanics; Complex Systems; Computational fluid dynamics; Dissociating gases; Dissociation; Engineering; Engineering Thermodynamics; Gas flow; Heat; Heat and Mass Transfer; Heat exchange; Heat exchangers; Heat transfer; Hydrogasdynamics in Technological Processes; Industrial Chemistry/Chemical Engineering; Nitrogen tetroxide; Nuclear energy; Numerical analysis; Thermal boundary layer; Thermodynamics; Thickness; Turbulent flow; chemical reaction; computational hydrodynamics; heat exchange; dissociation; boundary layer
• ISSN: 1062-0125; 1573-871X
• DOI: 10.1007/s10891-021-02314-9

Results of investigations of the heat exchange in the turbulent flow of nitrogen tetroxide in a cylindrical channel are presented. The equilibrium stage of the dissociation reaction N
2
O
4
⇄ 2NO
2
was considered. It was established that an increase in the temperature of the wall of the channel leads to an intensification of the chemical reaction proceeding in the N
2
O
4
flow and causes the absorption of the heat, transferred from the channel wall, in this flow to increase, with the result that the temperature of the near-wall layers and the thickness of the thermal boundary layer in the chemically reactive gas flow decrease to a level lower than those of a chemically inert heat-transfer agent. It is shown that the use of a dissociating heat-transfer agent in a short channel is advantageous in the case where the rate of its flow is small, and, to increase the efficiency of heat exchange in a high-velocity flow of such an agent, it is necessary to increase the length of a heat exchanger. Approximation formulas for determining the criteria of heat exchange in flows of chemically inert and reactive gases have been obtained.