Heat transfer at the nose of a blunt body in a rarefied supersonic flow of a nitrogen-hydrogen mixture

The temperature-recovery factor and specific heat flux have been measured at the nose of a spherically blunted body in a low-density supersonic stream of a nitrogen-hydrogen mixture. The experiments were carried out in the transition flow regime from continuous to free-molecular flow. The measurements show that the values of the recovery factor and heat flux in the mixture are larger than in the pure gases.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 6, pp. 88–91, November–December, 1973.The authors are grateful to I. F. Zavarzina and P. G. Itin for assistance.     

Calculation of supersonic equilibrium-dissociating air-xenon mixture flow past a blunt body

The flow of an equilibrium-reacting multicomponent three-element air-xenon mixture is numerically investigated. The effect of multicomponent diffusion on the convective heat transfer to the body surface is examined. The dependence of the convective heat transfer to the body surface and the total shock-layer spectral radiation flux P_m on the xenon concentration is obtained. A comparison of the calculated data for P_m and the experimental data of [2] gives good agreement. A simple approximation for the convective heat flux at the stagnation point as a function of xenon concentration is proposed.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 156–164, July–August, 1991.In conclusion the authors wish to thank I. A. Sokolova for supplying data on the resistance coefficients of the various mixtures and S. A. Yunitskii for discussing the numerical method.     

Flow around a sphere by a two-phase supersonic jet

Results are presented of a calculation of the flow around a sphere of a two-phase supersonic jet, discharging into a vacuum. Calculations were performed by the determination method with use of a difference grid constructed on the basis of characteristic ratios [1], The parameters of the unperturbed jet were determined with the two-velocity and two-temperature model of mutually penetrating flows of continuous media (gas and particles) [2, 3] by the network method [4]. In calculating the flow around the sphere, as in [5–7], it was assumed that the particles do not affect the gas flow in the shock layer. An analysis of the effect of particles on gasdynamic parameters in a shock layer was performed in [8].Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 171–176, November–December, 1978.The authors are grateful to A. N. Nikulin for providing the program for calculation of flow about a blunt body by a uniform supersonic flow.     

Numerical analysis on cooling performance of counterflowing jet over aerodisked blunt body

This study investigates a combined technique of both an active flow control concept that uses counterflowing jets and an aerodisk spike as a new method to significantly modify external flowfields and heat reduction in a hypersonic flow around a nose cone. The coolant gas (Carbon Dioxide and Helium) is chosen to inject from the tip of the nose cone to cool the recirculation region. The gases are considered to be ideal, and the computational domain is axisymmetric. The analysis shows that the counterflowing jet has significant effects on the flowfield and reduces the heat load over the nose cone. The Helium jet is found to have a relatively more effective cooling performance.     

Combustible mixture flow ahead of a blunt body

A solution is given in [1] for the problem of the supersonic flow of a combustible gas mixture past a sphere, using one of the simplest models of the combustion zone structure. The entire flow behind the shock wave in this model consists of two regions of adiabatic flow-an induction region and a region of equilibrium flow of combustion products-separated by the combustion front. Mixture passage through the front is accompanied by instantaneous combustion. The solution is given only for the subsonic and transonic regions.In the following the same problem is solved under the assumption that the reactions behind the combustion front proceed in equilibrium. The model used is that of a two-component mixture of the initial and combustion products with a single first-order chemical reaction taking place. This model is used to illustrate the effect of nonequilibrium on the flow pattern and the distribution of the functions in the shock layer. The solution may be used in the vicinity of the axis of symmetry for the case of combustible mixture flow past a blunt body of arbitrary shape.In conclusion the author wishes to thank G. G. Chernyi for his guidance in performing this study.     

Structure of a supersonic jet of an argon-helium mixture in a vacuum

Results of an experimental investigation of barodiffusion processes in supersonic jets of argon and helium mixtures by using an electron beam are presented.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 5, pp. 158–163, September–October, 1970.     

Combined method of calculating supersonic ideal-gas flow over a wing with a supersonic blunt leading edge

A combined numerical method, based on the successive calculation of the flow regions near the blunt leading edge and center of a wing, is proposed on the assumption that the angle of attack and the relative thickness and bluntness radius of the leading edge are small. The flow in the neighborhood of the leading edge of the wing is assumed to be identical to that on the windward surface of a slender body coinciding in shape with the surface of the blunt nose of the wing and is numerically determined in accordance with [1]. The flow parameters near the center of the wing are calculated within the framework of the law of plane sections [2]. In both regions the equations of motion of the gas are integrated by the Godunov method. The flow fields around elliptic cones are obtained within the framework of the combined method and the method of [3], A comparative analysis of the results of the calculations makes it possible to estimate the region of applicability of the method proposed.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 159–164, January–February, 1989.The authors wish to express their gratitude to A. A. Gladkov for discussing their work, and to G. P. Voskresenskii, O. V. Ivanov, and V. A. Stebunov for making available a program for calculating supersonic flow over a wing with a detached shock.     

Flow regimes formed by a counterflow jet in a supersonic flow

Results on the effect of the dynamic pressure, Mach number, and temperature of a jet injected from a body upstream in a free supersonic flow on the formation of flow regimes are presented. Flow regimes that ensure the greatest decrease in the drag of the body are given, the mechanism of formation of the LPM flow structure is described, and an approximate criterion is found, which allows determination of the range of existence of various modes of jet penetration into the flow.     

Calculation of supersonic viscid flow near stagnation line of a blunt body

A numerical study is made of supersonic flow of a viscous gas in the vicinity of the stagnation line of plane and axisymmetric blunt bodies (cylinder, sphere). As in [1–5], which consider the compressed layer of a viscous gas in the vicinity of the stagnation point, use is made of the locally self-similar approximation, which is used to transform the Navier-Stokes equations into a system of ordinary differential equations. In the present paper the solution is sought with the simplifications of [5] and with more general conditions, which makes it possible to study a broad class of flows. The proposed numerical algorithm permits obtaining the structure of the compressed layer near the stagnation line, including the shock wave and the boundary layer. The calculations made on a computer for different flow conditions are illustrated by graphs.The author wishes to thank G. I. Petrov, G. F. Telenin, and L. A., Chudov for their interest in the study and for their helpful discussions. discussions.     

Effect of blowing on supersonic dust-laden gas flow round a blunt body

One of the main problems which arise in the design of high-speed aircraft is the protection of the streamline surfaces against the erosion effect of solid particles and drops occurring in the free stream. For this purpose it is possible to use the device of blowing cold gas. This leads to the formation of a boundary layer of high density in which the particles are decelerated [1]. The present study investigates the effectiveness of this method of erosion protection in the example of supersonic flow round a sphere.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 178–181, March–April, 1986.     

Flow over blunt cones during entry into an atmosphere of carbon dioxide and nitrogen

An investigation has been made of hypersonic flow over spherically blunted cones in an atmosphere consisting of carbon dioxide and nitrogen. Local thermodynamic equilibrium is assumed in the shock layer. Account is taken of viscosity, diffusion, heat conduction, and radiative energy transport. The problem is solved using equations for dynamics of a viscous radiating gas without isolating inviscid flow and boundary-layer regions in the shock layer. The selectivity of the radiation is allowed for by using a two-stage approximation for the spectral dependence of the absorption coefficient, obtained by processing detailed data on absorption cross sections. The solution is found by a flow establishment method. Results are presented for flow over blunt cones with different semiangles.     

Accuracy of asymptotic solutions for nonuniform supersonic flow past a blunt body

Moscow. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 1, pp. 61–66, January–February, 1994.     

Strong mass injection at the surface of a blunt body in a supersonic flow

The case of supersonic flow over a blunt body when another gas is injected through the surface of the body in accordance with a given law is theoretically investigated. If molecular transport processes are neglected, the flow between the shock wave and the surface of the body should be regarded as two-layer, that is, as consisting of the flow in the shock layer between the shock wave and the contact surface and the flow in the layer of injected gas. A numerical solution of the problem is obtained near the front of the body and its accuracy is estimated. Approximate analytic solutions are obtained in the injected-gas layer: a constant-density solution and a solution of the boundary-layer type in the local similarity approximation. Near the flow axis the numerical and analytic solutions are fairly close, but at a distance from the axis the assumptions made reduce the accuracy of the approximate solutions. The flow in question can serve as a gas-dynamic model of a series of problems describing the radiant heating of blunt bodies in a hypersonic flow. In the presence of intense radiative heat transfer, vaporization is so great that the thickness of the vapor layer is comparable with the thickness of the shock layer. Moreover, the thermal shielding of various kinds of obstacles in channels through which a radiating plasma flows can be organized by means of the forced injection of a strong absorber. The formulation of a similar problem was reported in [1], but the results of the solution were not given. A two-layer model of the flow of an ideal gas over a blunt body was used in [2, 3] for the analysis of radiative heat transfer. In [2] the neighborhood of the stagnation point is considered. In [3] preliminary results relating to two-layer flow over blunt cones are presented. The solution is obtained by Maslen's approximate method.Moscow. Translated from Izvestiya Akademii Nauk SSSR. Mekhanika Zhidkosti i Gaza, No. 2, pp. 89–97, March–April, 1972.     

Flow of a mixture of gas and solid particles in supersonic underexpanded jets

The presence of a second phase in a gas jet flowing out of a nozzle leads to considerable changes in the flow pattern [1–3]. Thus, as the particle concentration increases, the central jump in compression [shock wave] moves in the direction of the nozzle cutoff, while the Mach number on the axis of the jet in front of the forward jump diminishes. In this paper we shall consider the numerical solution of the problem of an axisymmetrical, two-phase, underexpanded jet flowing out of a straight nozzle into a submerged space. It is assumed that the distribution of the flow parameters is uniform over the jet cross section and that no thermal or dynamic retardation of the particles occurs.