scholarly journals Computational studies to determine the design of prototype heater for a hypersonic wind tunnel

2021 ◽  
Vol 2057 (1) ◽  
pp. 012003
Author(s):  
A S Rtishcheva
Keyword(s):  
Heat Flux ◽  
Wind Tunnel ◽  
Stokes Equations ◽  
Thermal State ◽  
Navier Stokes ◽  
Computational Studies ◽  
Central Electrode ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Hypersonic Wind Tunnel

Abstract During the modernization of the TsAGI hypersonic wind tunnel, which implies an increase in the limiting values of the flow stagnation parameters, and in the thermal load, consequently, computational studies were realized for the existing design of the electric arc heater and new geometry options for the central electrode and the cooling duct of the external electrode and nozzle. The distribution of the heat flux density to the surfaces of the main elements of the wind tunnel was obtained based on the calculations for the air duct of wind tunnel. The qualitative data of the flow formation both in the pre-heater and the pre-chamber served as the basis for changing the geometry of the central electrode. In this study, a numerical modelling approach was implemented for a through calculation of the flow and heat transfer in all areas of the wind tunnel circuit (heater, pre-chamber, nozzle, test section, diffuser). The ANSYS FLUENT software package was used to solve the axisymmetric Navier-Stokes equations for a five-component chemically reacting gas mixture: O2; N2; O; N; NO using the Spalart-Allmaras turbulence model. To study the hydrodynamics and thermal state of the structure of the external and central electrodes, the possibility of the ANSYS FLUENT complex for solving conjugate problems was used (the complete Navier-Stokes equations and the energy balance equation were solved in a fluid, and the heat conduction equation was solved in a solid). In this case, at the interface between the media, the conditions for the continuity of temperature and heat flux were satisfied.

scholarly journals INVESTIGATION HYPERBOLIC PARABOLOID SHELL IN THE WIND TUNNEL AND COMPARISON WITH NUMERICAL SIMULATIONS

2018 ◽  
Vol 64 ◽  
Author(s):  
V.V. Stojanov ◽  
S. Jgalli
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Wind Flow ◽  
Hyperbolic Paraboloid ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Basic Model ◽  
The Impact

There are different ways to determine aerodynamic parameters, using analytical and experimental data for analyzing the behavior of structures when exposed to wind load. To date, the most developed is considered a numerical method for determining the characteristics of the above methods, based on the numerical solution of the Navier-Stokes equations. The accuracy of the results obtained using such a calculation method and obtaining the values of aerodynamic forces has increased due to the revision of mathematical models and the development of software complexes for the discretization of object bodies. This article gives an analytical overview of the results of research in the field of study the impact of wind loads on hypar (shell square in plan with the form of a hyperbolic paraboloid). The features of the investigated forms a discretization surface depending on pressure coefficients obtained in foreign literatures. Particular attention is paid to the numerical determination of aerodynamic coefficients on the surfaces of a hyperbolic paraboloid. The results were discussed and the nature of the distribution of coefficients depending on the angle of attack of the wind. Achieved analytical comparison computer modeling turbulent wind flows, based on solving the Reynolds equations arising from the use of averaging the Navier-Stokes equations. The basic model of turbulence such as: k-ε Standard Model; MMK; DBN; Shear-Stress Transport k-ω model; Transition k-kl-ω model. The possibility of choosing one or another model depending on the properties and characteristics of the wind flow is analyzed, for application in numerical simulation of wind flow around hyperbolic shells. The same was done, a comparative analysis of the results of physical testing in a wind tunnel with a numerical simulation in Ansys Fluent.

The inlet flow structure of a conceptual open-nose supersonic drone

2021 ◽  
pp. 095441002098304
Author(s):  
Eiman B Saheby ◽  
Xing Shen ◽  
Anthony P Hays ◽  
Zhang Jun
Keyword(s):  
Flow Structure ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Computational Fluid Dynamic Simulation ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Aerodynamic Efficiency ◽  
Performance Effects

This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.

Numerical Analysis of Streamlines in Kaplan Turbine with Different Distributor Fins Design

2020 ◽  
Vol 35 ◽  
pp. 46-54
Author(s):  
Daniele Twardowski ◽  
Diego Alves de Miranda
Keyword(s):  
Stokes Equations ◽  
Turbine Blades ◽  
Navier Stokes ◽  
Flow Profile ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Kaplan Turbine ◽  
Current Lines ◽  
High Level ◽  
Volume Method

With each passing day companies are looking more and more in the initial phase of the project, to understand the phenomena arising, so that in the execution of the project there are no failures, much less when the project is in operation. For this, the numerical simulation has been shown an increasingly efficient tool to assist the engineers and designers of machines and equipment. The Kaplan turbine design requires a high level of engineering expertise combined with a high level of knowledge in fluid mechanics, as poor design of a diffuser fin can lead to disordered turbulent flow which, when mixed with a high pressure drop, can cavitate into turbine blades. The aim of this study is to evaluate different types of diffuser fin profiles in the inlet at Kaplan turbines. For this, numerical computer simulation was used with the aid of the Ansys Fluent software, in which simulations of water flow in a steady state occurred. The software works with the finite volume method for the discretization of the Navier-Stokes equations. The simulations have proved to be efficient in capturing current lines and pointing out the best flow profile in a project, avoiding more complex turbine blade problems.

Axisymmetric Stagnation—Point Flow and Heat Transfer of a Viscous Fluid on a Rotating Cylinder With Time-Dependent Angular Velocity and Uniform Transpiration

2006 ◽  
Vol 129 (1) ◽  
pp. 106-115 ◽  
Author(s):  
A. B. Rahimi ◽  
R. Saleh
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Angular Velocity ◽  
Stokes Equations ◽  
Time Dependent ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow And Heat Transfer ◽  
Self Similar

The unsteady viscous flow and heat transfer in the vicinity of an axisymmetric stagnation point of an infinite rotating circular cylinder with transpiration U0 are investigated when the angular velocity and wall temperature or wall heat flux all vary arbitrarily with time. The free stream is steady and with a strain rate of Γ. An exact solution of the Navier-Stokes equations and energy equation is derived in this problem. A reduction of these equations is obtained by the use of appropriate transformations for the most general case when the transpiration rate is also time-dependent but results are presented only for uniform values of this quantity. The general self-similar solution is obtained when the angular velocity of the cylinder and its wall temperature or its wall heat flux vary as specified time-dependent functions. In particular, the cylinder may rotate with constant speed, with exponentially increasing/decreasing angular velocity, with harmonically varying rotation speed, or with accelerating/decelerating oscillatory angular speed. For self-similar flow, the surface temperature or its surface heat flux must have the same types of behavior as the cylinder motion. For completeness, sample semi-similar solutions of the unsteady Navier-Stokes equations have been obtained numerically using a finite-difference scheme. Some of these solutions are presented for special cases when the time-dependent rotation velocity of the cylinder is, for example, a step-function. All the solutions above are presented for Reynolds numbers, Re=Γa2∕2υ, ranging from 0.1 to 1000 for different values of Prandtl number and for selected values of dimensionless transpiration rate, S=U0∕Γa, where a is cylinder radius and υ is kinematic viscosity of the fluid. Dimensionless shear stresses corresponding to all the cases increase with the increase of Reynolds number and suction rate. The maximum value of the shear stress increases with increasing oscillation frequency and amplitude. An interesting result is obtained in which a cylinder rotating with certain exponential angular velocity function and at particular value of Reynolds number is azimuthally stress-free. Heat transfer is independent of cylinder rotation and its coefficient increases with the increasing suction rate, Reynolds number, and Prandtl number. Interesting means of cooling and heating processes of cylinder surface are obtained using different rates of transpiration.

scholarly journals Effect of Leading-Edge Bulges on Aerodynamic Characteristics of Bionic Wingsail

2021 ◽  
Author(s):  
Chen Li ◽  
Peiting Sun ◽  
Hongming Wang
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Suction Surface ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Extension Direction ◽  
Lift And Drag

The leading-edge bulges along the extension direction are designed on the marine wingsail. The height and the spanwise wavelength of the protuberances are 0.1c and 0.25c, respectively. At Reynolds number Re=5×105, the Reynolds Averaged Navier-Stokes equations are applied to the simulation of the wingsail with the bulges thanks to ANSYS Fluent finite-volume solver based on the SST K-ω models. The grid independence analysis is carried out with the lift and drag coefficients of the wingsail at AOA = 8° and AOA=20°. The results show that while the efficiency of the wingsail is reduced by devising the leading-edge bulges before stall, the bulges help to improve the lift coefficient of the wingsail when stalling. At AOA=22° under the action of the leading-edge tubercles, a convective vortex is formed on the suction surface of the modified wingsail, which reduces the flow loss. So the bulges of the wingsail can delay the stall.

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.

scholarly journals INVESTIGATION OF GAS-DYNAMIC PROCESSES IN PIPELINE COMMUNICATIONS DURING THEIR TRENCHLESS RECONSTRUCTION WITH THE TECHNOLOGY "TRACTION PISTON"

2019 ◽  
pp. 43-53
Author(s):  
K. A. Poliarush
Keyword(s):  
Stokes Equations ◽  
Air Flow ◽  
Longitudinal Section ◽  
Cfd Modeling ◽  
Navier Stokes ◽  
Dynamic Processes ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Software Complex ◽  
Gas Dynamic

The technology of the trenchless reconstruction of pipeline communications "Traction Piston", which consists in running a new polyethylene pipeline into a steel one worn by pigis described. At the same time, in order to maintain the necessary pressure in the cavity, the space between the new polyethylene pipeline and the worn steel one is sealed. A 3D modeling of the annulus and space behind the piston, where the complex turbulent flow of air flows, is carried out. A CFD modeling of gas-dynamic processes in the annulus and space behind the piston while laying a worn steel pipeline with a polyethylene pipeline in the ANSYS Fluent software system is performed. The mathematical model is based on the solution of the Navier-Stokes equations and the continuity of the flow closed by a two-parameter turbulence model of Launder-Sharma with the use of a wall function with corresponding initial and boundary conditions. A dynamic grid model was used to simulate the motion of the piston and the polyethylene pipeline. The type of adjustment of the dynamic grid parameters during the stroke of a new polyethylene pipeline into a defective steel one – Layering was chosen. The simulation results were visualized in the postprocessor of the software complex by constructing flow lines, velocity vectors, pressure fields on the contours and in the longitudinal section of the annulus and space behind the piston. The exact values of velocity, pressure at different points between the annulus and space behind the piston were determined. The structure of the air flow in the cavity and interstitial space is studied. The places of slowdown and acceleration of air flow, falling and increase of pressure are found. The loss of pressure in the annular space is determined.

Research of Measurement Method of Two Dimensional Configuration Drag Test in Wind Tunnel in Case of High Lift

2011 ◽  
Vol 301-303 ◽  
pp. 671-676
Author(s):  
Yu Qin Jiao ◽  
Xi Ping Chen ◽  
Zhen Li Zhi
Keyword(s):  
Wind Tunnel ◽  
Stokes Equations ◽  
Wind Tunnel Test ◽  
Flow Characteristics ◽  
Aerodynamic Performance ◽  
Wake Flow ◽  
Navier Stokes ◽  
Two Dimensional ◽  
High Lift ◽  
Navier Stokes Equations

Computational fluid dynamics and wind tunnel test are two main technical means to examine the aerodynamic performance of airfoil and two-dimensional(2-D) configuration. Two dimensional wind tunnel tests use commonly wake flow field measurement to integrate for drag of airfoil or two-dimensional configuration, but the integral formulas are based on certain assumptions and of certain bounds of application. In this paper, based on Navier-Stokes equations numerical simulation and two dimensional wind tunnel testing, the drag measuring technique for high lift configuration in low speed wind tunnel is researched. Navier-Stokes equations is solved for the flow around a multi-element airfoil, the wake flow characteristics behind the multi-element airfoil and the assumptions for conventional drag measuring method are analyzed, then a new more precise drag formula for two dimensional wind tunnel test is put forward; Based on the simulation results of multi-element airfoil flow, it’s aerodynamic performance is obtained respectively by integrating the surface pressure and friction drag, and computing with the information of wake flow according to conventional and newly proposed drag calculation formulas, and the three results are compared to verify the accuracy of the new drag formula; The wind tunnel test is carried out to ascertain the accuracy of the new drag formula. It is shown from the results that in the high-lift case the conventional drag formula with the wake information is of many limitations and must be improved, and the new drag formula presented in this paper is more accurate because of consideration of the wake flow characteristics of airfoil or two-dimensional configuration.

Evaporation of a Saltwater Film in a Vertical Channel and Comparison With the Case of the Freshwater

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
A. Belhadj Mohamed ◽  
Iskander Tlili
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Stokes Equations ◽  
Vertical Channel ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Nonlinear Form ◽  
Mass Transfers

Abstract In this paper, we analyze the evaporation of a seawater film by mixed convection of humid air. The flown plate is heated and the second plate is dry and can exchanges heat with the environment, be isothermal or adiabatic. Using adequate approximations, we build up a nonlinear form of the Navier–Stokes equations, which is specific for the boundary layer case. We take into account the variation of the salt concentration because of the phase change along the vertical channel. Consequently, to find a solution for combined heat and mass transfers through the channel, we use a numerical finite difference method. The effect of salinity on transfer is taken into account. We found that adding salt to freshwater economizes energy to enhance the film temperature, and the latent heat flux is lower. In addition, we show that the influence of film matter quantity is clearer for saltwater when compared with freshwater case. However, we demonstrate that the effect of the film temperature at the entry and supply heating variations reminds constantly if we compare saltwater and freshwater.

Numerical Simulation on the Aerodynamic Characteristics Effect of Ribs Acting on the Cooling Tower

2017 ◽  
Vol 259 ◽  
pp. 227-231
Author(s):  
Petr Harazim ◽  
Lukáš Vráblík
Keyword(s):  
Cooling Tower ◽  
Stokes Equations ◽  
Meridional Wind ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Infinite Cylinder ◽  
Turbulent Model ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Critical Flow Regime

The experimental work deals with the modelling of flow around a two-dimensional model of an infinite cylinder in a trans-critical flow regime. Herein, there was used ANSYS Fluent and the turbulent model k-ε realizable for the calculation of the pressure distribution around the cylinder. This turbulence model belongs to Reynolds Averaged Navier-Stokes equations (RANS). The simulated numerical domain considered half of the cylinder with the diameter of 70 m, wind flow was set to 35 m.s-1, which resulting in the Reynolds number of Re = 1,68.108. In this study, meridional wind ribs were modelled physically. A parametric study was modelled with the different shape of ribs, ribs spacing and height. Simulated results were compared with experimentally ascertained data and guidelines.

Sign in / Sign up

Export Citation Format

Share Document