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.

scholarly journals Study of heat transfer processes in the flowing part of hypersonic air-ramjet engine

2018 ◽  
Vol 194 ◽  
pp. 01037
Author(s):  
Eugene Maslov ◽  
Irina Zharova ◽  
Valery Faraponov ◽  
Eugene Kozlov ◽  
Vladislav Matskevich
Keyword(s):  
Heat Transfer ◽  
Gas Dynamics ◽  
Gas Flow ◽  
Theoretical Study ◽  
Transfer Processes ◽  
Ramjet Engine ◽  
Mach Numbers ◽  
Flowing Channel

The technique and results of the experimental-theoretical study of gas dynamics, heat transfer and the structure of gas flow in the flowing channel of a model hypersonic air-ramjet engine are presented for Mach numbers M = (5; 6).

Numerical Simulation on Process of Flow and Heat Transfer in Upright Magnesium Reducing Furnace

2011 ◽  
Vol 383-390 ◽  
pp. 6657-6662 ◽  
Author(s):  
Jun Xiao Feng ◽  
Qi Bo Cheng ◽  
Si Jing Yu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Flue Gas ◽  
Gas Flow ◽  
Three Dimensional ◽  
Reaction Heat ◽  
Flow And Heat Transfer ◽  
Major Factors ◽  
High Chemical Reaction

Based on the analysis of structural characteristic superiority, the process of combustion, flue gas flow and heat transfer in the upright magnesium reducing furnace, the three dimensional mathematical model is devoloped. And numerical simulation is performed further with the commercial software FLUENT. Finally, the flow and temperature field in furnace and temperature field in reducing pot have been obtained. The results indicate that the upright magnesium reducing furnace has perfect flue gas flow field and temperature field to meet the challenge of the magnesium reducing process; the major factors that affect the magnesium reducing reaction are the low thermal conductivity of slag and the high chemical reaction heat absorption.

Numerical Simulation of Gas Flow Pattern in Cyclone Spray Scrubber

2011 ◽  
Vol 233-235 ◽  
pp. 701-706
Author(s):  
Bing Tao Zhao ◽  
Yi Xin Zhang ◽  
Kai Bin Xiong
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Flow Pattern ◽  
Gas Flow ◽  
Stokes Equations ◽  
Tangential Velocity ◽  
Navier Stokes ◽  
Computational Domain ◽  
Spray Scrubber ◽  
Cfd Method

The numerical simulation of the fluid flow is presented by CFD technique to characterize the flow pattern of cyclone spray scrubber. In this process, the Reynolds-averaged Navier-Stokes equations with the Reynolds stress turbulence model (RSM) for fluid flow are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the fluid computational domain. According to the computational results, the tangential velocity, axial velocity and turbulence intensity of the gas flow are addressed in the different flowrate. The results indicate that the CFD method can effectively reveal the mechanism of gas flow in the cyclone spray scrubber.

scholarly journals METHOD OF PARALLELIZATION OF NUMERICAL ALGORITHMOF NAVIER-STOKES EQUATIONS COMPLETE SYSTEM

2016 ◽  
pp. 92-98
Author(s):  
R. E. Volkov ◽  
A. G. Obukhov
Keyword(s):  
Thermal Conductivity ◽  
Gas Flow ◽  
Stokes Equations ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Computation Time ◽  
Navier Stokes ◽  
Heat Conducting ◽  
Navier Stokes Equations ◽  
Comparison Of The Results

The article considers the features of numerical construction of solutions of the Navier-Stokes equations full system describing a three-dimensional flow of compressible viscous heat-conducting gas under the action of gravity and Coriolis forces. It is shown that accounting of dissipative properties of viscosity and thermal conductivity of the moving continuum, even with constant coefficients of viscosity and thermal conductivity, as well as the use of explicit difference scheme calculation imposes significant restrictions on numerical experiments aimed at studying the arising complex flows of gas or liquid. First of all, it is associated with a signifi- cant complication of the system of equations, the restrictions on the value of the calculated steps in space and time, increasing the total computation time. One of the options is proposed of algorithm parallelization of numerical solution of the complete Navier - Stokes equations system in the vertical spatial coordinate. This parallelization option can significantly increase the computing performance and reduce the overall time of counting. A comparison of the results of calculation of one of options of gas flow in the upward swirling flow obtained by serial and parallel programs is presented.

Numerical simulation of complex gas flows in concentrated fire vortices

2019 ◽  
Vol 5 (3) ◽  
pp. 47-68
Author(s):  
Sergei P. Bautin ◽  
Alexandr G. Obukhov
Keyword(s):  
Numerical Simulation ◽  
Stokes Equations ◽  
Local Heating ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Initial Boundary ◽  
Gas Flows ◽  
Heat Conducting ◽  
Russian Academy Of Sciences ◽  
Academy Of Sciences

This article presents the results of numerical simulation of free fire vortices arising in laboratory conditions. The authors demonstrate the possibility of obtaining such concentrated fire vortices in a series of experimental studies conducted under the supervision of A. &nbsp;Yu. &nbsp;Varaksin, a corresponding member of the Russian Academy of Sciences, at the Joint Institute for High Temperatures of the Russian Academy of Sciences.<br> The authors propose to consider the analytical and numerical studies of arising complex swirling gas flows during local heating of a metal underlying surface by several sources from the point of view of gas dynamics. When considering complex flows of a heating gas as a motion of a viscous, heat-conducting, and compressible continuous medium, the complete system of Navier&nbsp;— Stokes equations is used. The proposed initial-boundary conditions made it possible to numerically determine the main gas-dynamic characteristics of the resulting three-dimensional and unsteady gas flows in free fire vortices.<br> The calculation results showed that during the formation of fiery vortices, several stages are distinguished in their development. The first stage is characterized by the occurrence of local gas flows diverging in the radial direction from the heating regions. The second stage is accompanied by the formation in the regions of the location of the heating sources of local vortices with opposite spin directions. The third stage is characterized by the fact that from smaller vortices due to the intense influx of external air a common large thermal vortex is formed, which receives a positive twist under the influence of the Coriolis force. At the fourth stage, with an increase in the rotation speed, a decrease in the vertical dimensions of the thermal vortex and its decay into several small ones is observed. Thus, the completion of the life cycle of one concentrated vortex is replaced by the formation of a new one. For the initial parameters, the lifetime of the concentrated thermal vortex is about one minute.

RESEARCH OF CONICAL BODIES INTERACTIONS WITH IRREGULAR SUPERSONIC FLOW AT SMALL ATTACK ANGLES

2020 ◽  
Author(s):  
Евгений Алексеевич Прокопенко ◽  
Артем Васильевич Шевченко ◽  
Сергей Алексеевич Яшков ◽  
Игорь Анатольевич Дема ◽  
Тимофей Андреевич Житников ◽  
...  
Keyword(s):  
Supersonic Flow ◽  
Wind Tunnel ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Perfect Gas ◽  
Navier Stokes Equations ◽  
Mach Numbers ◽  
Experimental Researches

В статье представлены теоретические и экспериментальные исследованиях сверхзвукового потока вблизи конических тел при различных числах Маха. Экспериментальные исследования выполнены с помощью сверхзвуковой атмосферно-вакуумной аэродинамической трубы Военно-космической академии имени А.Ф.Можайского. В основу теоретического исследования положена модель вязкого совершенного газа, описываемая уравнениями Навье-Стокса. The article presents theoretical and experimental researches of supersonic flow near conical bodies at various Mach numbers. Experimental researches were carried out using a supersonic atmospheric-vacuum wind tunnel of Mozhaisky Military Space Academy. The theoretical researches is based on the model of a viscous perfect gas described by the Navier-Stokes equations.

Three-Dimensional Numerical Analysis of Gas Flow and Heat Transfer in SOFCs With Honeycomb-Like Channels

2010 ◽  
Author(s):  
Yuan Huang ◽  
Weiguo Wang ◽  
Jinliang Yuan ◽  
Bengt Sunden
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Diffusion Layer ◽  
Gas Flow ◽  
Stokes Equations ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Gas Diffusion ◽  
Factors Affecting

Design of advanced flow channels in bipolar plates is one of the key factors affecting SOFC stack and system performance. Various transport phenomena occurring in SOFCs with conventional interconnects with rib- or serpentine channels, etc, have been extensively studied. In this paper new designed channels are proposed and evaluated numerically by computational software. The investigated geometry consists of two computational domains: a porous anode layer and interconnect. The latter one serves as gas distribution for hydrogen or air in SOFCs. Compared with conventional designs, the configuration of interconnect having honeycomb structures is different. Such unique channels lead to gas flow in many directions, and gas flow distribution and pressure drop are significantly different from those in conventional designs. This simulation employs the Navier-Stokes equations for the gas flow in the channels, and the Darcy model in the porous layer. Combined gas and heat transfer in the channels and the porous gas diffusion layer, permeation across the interface are analyzed by a fully three-dimensional code in this paper. All the governing equations are solved utilizing the commercial code COMSOL. The velocity field, the distribution of hydrogen in the channels, the fraction of the hydrogen entering the anode diffusion layer, and the pressure drop are predicted and presented. Also, the friction factor of the unique design is compared with that of the rectangular channel. The numerical results and findings from this study are important for optimizing the flow fields, decreasing the cost of experiments and designing of the channels.

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