TY - JOUR

T1 - Rate Effects in Hypersonic Flows

AU - Candler, Graham V.

PY - 2019/1/5

Y1 - 2019/1/5

N2 - Hypersonic flows are energetic and result in regions of high temperature, causing internal energy excitation, chemical reactions, ionization, and gas-surface interactions. At typical flight conditions, the rates of these processes are often similar to the rate of fluid motion. Thus, the gas state is out of local thermodynamic equilibrium and must be described by conservation equations for the internal energy and chemical state. Examples illustrate how competition between rates in hypersonic flows can affect aerodynamic performance, convective heating, boundary layer transition, and ablation. The conservation equations are outlined, and the most widely used models for internal energy relaxation, reaction rates, and transport properties are reviewed. Gas-surface boundary conditions are described, including finite-rate catalysis and slip effects. Recent progress in the use of first-principles calculations to understand and quantify critical gas-phase reactions is discussed. An advanced finite-rate carbon ablation model is introduced and is used to illustrate the role of rate processes at hypersonic conditions.

AB - Hypersonic flows are energetic and result in regions of high temperature, causing internal energy excitation, chemical reactions, ionization, and gas-surface interactions. At typical flight conditions, the rates of these processes are often similar to the rate of fluid motion. Thus, the gas state is out of local thermodynamic equilibrium and must be described by conservation equations for the internal energy and chemical state. Examples illustrate how competition between rates in hypersonic flows can affect aerodynamic performance, convective heating, boundary layer transition, and ablation. The conservation equations are outlined, and the most widely used models for internal energy relaxation, reaction rates, and transport properties are reviewed. Gas-surface boundary conditions are described, including finite-rate catalysis and slip effects. Recent progress in the use of first-principles calculations to understand and quantify critical gas-phase reactions is discussed. An advanced finite-rate carbon ablation model is introduced and is used to illustrate the role of rate processes at hypersonic conditions.

KW - aerothermodynamics

KW - finite-rate processes

KW - high-temperature gas dynamics

KW - hypersonic aerodynamics

KW - nonequilibrium flows

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U2 - 10.1146/annurev-fluid-010518-040258

DO - 10.1146/annurev-fluid-010518-040258

M3 - Review article

AN - SCOPUS:85059620317

VL - 51

SP - 379

EP - 402

JO - Annual Review of Fluid Mechanics

JF - Annual Review of Fluid Mechanics

SN - 0066-4189

ER -