Study of gas flow in region of incidence of a shock on a cylinder in high supersonic flow

1971 ◽  
Vol 2 (2) ◽  
pp. 98-100 ◽  
Author(s):  
M. P. Teterin
Keyword(s):  
Supersonic Flow ◽  
Gas Flow

Computational study of unsteady gas flow in the combustion chamber of a ramjet engine with heat transfer

2021 ◽  
pp. 50-61
Author(s):  
Надежда Петровна Скибина
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Supersonic Flow ◽  
Combustion Chamber ◽  
Gas Flow ◽  
Stokes Equations ◽  
Heat Conducting ◽  
Measuring Device ◽  
Ramjet Engine ◽  
Mach Numbers

Проведено численное исследование нестационарного турбулентного сверхзвукового течения в камере сгорания прямоточного воздушно-реактивного двигателя. Описана методика экспериментального измерения температуры на стенке осесимметричного канала в камере сгорания двигателя. Математическое моделирование обтекания исследуемой модели двигателя проводилось для скоростей набегающего потока M = 5 ... 7. Начальные и граничные условия задачи соответствовали реальному аэродинамическому эксперименту. Проанализированы результаты численного расчета. Рассмотрено изменение распределения температуры вдоль стенки канала с течением времени. Проведена оценка согласованности полученных экспериментальных данных с результатами математического моделирования. Purpose. The aim of this study is a numerical simulation of unsteady supersonic gas flow in a working path of ramjet engine under conditions identical to aerodynamic tests. Free stream velocity corresponding to Mach numbers M=5 ... 7 are considered. Methodology. Presented study addresses the methods of physical and numerical simulation. The probing device for thermometric that allows to recording the temperature values along the wall of internal duct was proposed. To describe the motion of a viscous heat-conducting gas the unsteady Reynolds averaged Navier - Stokes equations are considered. The flow turbulence is accounted by the modified SST model. The problem was solved in ANSYS Fluent using finite-volume method. The initial and boundary conditions for unsteady calculation are set according to conditions of real aerodynamic tests. The coupled heat transfer for supersonic flow and elements of ramjet engine model are realized by setting of thermophysical properties of materials. The reliability testing of numerical simulation has been made to compare the results of calculations and the data of thermometric experimental tests. Findings. Numerical simulation of aerodynamic tests for ramjet engine was carried out. The agreement between the results of numerical calculations and experimental measurements for the velocity in the channel under consideration was obtained; the error was shown to be 2%. The temperature values were obtained in the area of contact of the supersonic flow with the surface of the measuring device for the external incident flow velocities for Mach numbers M = 5 ... 7. The process of heating the material in the channel that simulated the section of the engine combustion chamber was analyzed. The temperature distribution was studied depending on the position of the material layer under consideration relative to the contact zone with the flow. Value. In the course of the work, the fields of flow around the model of a ramjet engine were obtained, including the region of supersonic flow in the inner part of axisymmetric channel. The analysis of the temperature fields showed that to improve the quality of the results, it is necessary to take into account the depth of the calorimetric sensor. The obtained results will be used to estimate the time of interaction of the supersonic flow with the fuel surface required to reach the combustion temperature.

Transient source, doublet and vortex solutions of the linearized equations of supersonic flow

1950 ◽  
Vol 202 (1068) ◽  
pp. 40-53 ◽  
Keyword(s):  
Wave Equation ◽  
Supersonic Flow ◽  
Time Variation ◽  
Gas Flow ◽  
Step Function ◽  
Heaviside Step Function ◽  
Linearized Equations ◽  
Transient Source ◽  
Vortex Solutions ◽  
Compressible Gas Flow

By introducing the Heaviside step function as the time variation of the fundamental source solution of the wave equation of compressible gas flow, a family of ‘transient’ source and doublet solutions is derived, together with a generalization of the vortex, and their more interesting properties are explored. These results are applicable to unsteady supersonic aerofoil theory and similar problems.

scholarly journals Annular Supersonic Ejector Design and Optimization

2012 ◽  
Author(s):  
K. Sathiyamoorthy ◽  
Venkat S. Iyengar ◽  
P. Manjunath
Keyword(s):  
Molecular Weight ◽  
High Temperature ◽  
Supersonic Flow ◽  
Gas Flow ◽  
Optimization Procedure ◽  
Flow Region ◽  
Flow Passage ◽  
Design And Optimization ◽  
Supersonic Ejector ◽  
Total Temperature

An ejector is a device that entrains a secondary flow into a high speed stream that is generated by expansion of high pressure motive gas [1]. These ejectors can be broadly classified into central ejectors and annular ejectors. A large majority of applications involve central ejectors where the motive gas flow is injected along the centre of the flow passage of the secondary flow. Dutton and Carroll [2] proposed an optimization procedure for such ejectors without taking the mixed supersonic flow region into account and generated the design curves considering the constant Total temperature, Molecular weight and Specific heat ratios. However in some applications involving high temperature gases such as in ramjet/scramjet and gas turbine test facilities, an annular supersonic ejector is more appropriate where annular injection of the motive gas at the periphery of the flow passage is desired to avoid the exposure of the motive gas flow nozzle to the high temperature combustion product gases. A design and optimization procedure for an annular supersonic ejector based on the earlier approach [2] with the mixed supersonic flow region and incorporating variable Total temperature, Molecular weight and Specific heat ratios in the model has been developed based on simplified one dimensional constant area mixing model and verified using CFD software Fluent.

Compressible fluid flow

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Supersonic Flow ◽  
Gas Flow ◽  
Surface Friction ◽  
Perfect Gas ◽  
Flowing Fluid ◽  
Convergent Nozzle ◽  
One Dimensional ◽  
Compressible Fluid Flow ◽  
Flow Through ◽  
Key Parameter

Compressible-gas flow through convergent and convergent-divergent nozzles is analysed in this chapter based upon the conservation laws for mass, momentum, and energy, together with considerations of thermodynamics. It is shown that in both cases the key parameter in describing the flow is the Mach number, which is used to distinguish between subsonic and supersonic flow. So that significant results can be achieved, the flowing fluid is treated as a perfect gas, and the flow as one dimensional. Flow through a convergent nozzle and the choking limitation is discussed. Flow through a normal shockwave, which is an important feature of supersonic flow, is also analysed. No account is taken of surface friction or heat transfer, and the flow upstream and downstream of a shockwave is treated as isentropic. In addition, the conditions are discussed under which a shockwave arises in compressible flow through a convergent-divergent nozzle.

Influence of the Criteria of Similarity on the Exergy of the Gas Flow with Pulsed Energy Supply in The Expanding Channel of the Plane Shape

2011 ◽  
Vol 6 (1) ◽  
pp. 84-91
Author(s):  
Vladimir P. Zamuraev ◽  
Anna P. Kalinina
Keyword(s):  
Mach Number ◽  
Supersonic Flow ◽  
Energy Supply ◽  
Gas Flow ◽  
Specific Force ◽  
Variable Section ◽  
Number Flow ◽  
Plane Shape ◽  
Channel Expansion ◽  
Expanding Channel

The effect of influence of the parameters of similarity on the value of the exergy for supersonic flow in a channel of variable section with a pulsed-periodic energy supply is studied. The specific force acting on the walls of the expanding channel in dependence on the position, length of the zone of pulse-periodic energy supply, the Strouhal number and the Mach number flow is investigated. The following correlation is established: the specific force is increased and the exergy of the flow is used better with decreasing length of the zone of energy supply and with decreasing of distance between the zone and the place of beginning of the channel expansion. Raising the temperature at a single energy supply pulse may be considered as factor which increases specific force. It takes place at lower frequencies

TEM evaluation of graded SixGe1-x heterolayers

1991 ◽  
Vol 49 ◽  
pp. 894-895
Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Gas Flow ◽  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Dark Field ◽  
Bipolar Transistors ◽  
Structural Quality ◽  
Weak Beam ◽  
Transmission Electron ◽  
And Behavior

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.

Electron Microscopy/Diffraction Study of the Ternary Mn-Er-S System

1990 ◽  
Vol 48 (1) ◽  
pp. 76-77
Author(s):  
A. R. Landa Canovas ◽  
L.C. Otero Diaz ◽  
T. White ◽  
B.G. Hyde
Keyword(s):  
Electron Microscopy ◽  
Gas Flow ◽  
Graphite Crucible ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
X Ray ◽  
Intermediate Phases ◽  
Twin Band ◽  
Ar Gas

X-Ray diffraction revealed two intermediate phases in the system MnS+Er2S3,:MnEr2S4= MnS.Er2S3, and MnEr4S7= MnS.2Er2S3. Their structures may be described as NaCl type, chemically twinned at the unit cell level, and isostructural with CaTi2O4, and Y5S7 respectively; i.e. {l13} NaCl twin band widths are (4,4) and (4,3).The present study was to search for structurally-related (twinned B.) structures and or possible disorder, using the more sensitive and appropiate technigue of electron microscopy/diffraction.A sample with nominal composition MnEr2S4 was made by heating Mn3O4 and Er2O3 in a graphite crucible and a 5% H2S in Ar gas flow at 1500°C for 4 hours. A small amount of this material was thenannealed, in an alumina crucible, contained in sealed evacuated silica tube, for 24 days at 1100°C. Both samples were studied by X-ray powder diffraction, and in JEOL 2000 FX and 4000 EX microscopes.

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