Numerical analysis for heat shield ablation law in transpiration cooling system

1993 ◽  
Vol 2 (4) ◽  
pp. 260-265 ◽  
Author(s):  
Yan-Hou Xu ◽  
Zhao-Ji Yang
Keyword(s):  
Numerical Analysis ◽  
Cooling System ◽  
Heat Shield ◽  
Transpiration Cooling

A Numerical Analysis on the System Impedance in a Fan Cooling System

2003 ◽  
Author(s):  
Dong-Il Kim ◽  
Ki-So Bok ◽  
Han-Bae Lee
Keyword(s):  
Numerical Analysis ◽  
Pressure Drop ◽  
Flow Rate ◽  
Pressure Difference ◽  
Cooling System ◽  
Computational Time ◽  
Computational Domain ◽  
Impedance Curve ◽  
Fan Cooling ◽  
Large Investment

To seek the fan operating point on a cooling system with fans, it is very important to determine the system impedance curve and it has been usually examined with the fan tester based on ASHRAE standard and AMCA standard. This leads to a large investment in time and cost, because it could not be executed until the system is made actually. Therefore it is necessary to predict the system impedance curve through numerical analysis so that we could reduce the measurement time and effort. This paper presents how the system impedance curve (pressure drop curve) is computed by CFD in substitute for experiment. In reverse order to the experimental principle of the fan tester, pressure difference was adopted first as inlet and outlet boundary conditions of the system and then flow rate was calculated. After determining the system impedance curve, it was compared with experimental results. Also the computational domain of the system was investigated to minimize computational time.

scholarly journals Effects of Coolants of Double Layer Transpiration Cooling System in the Leading Edge of a Hypersonic Vehicle

2021 ◽  
Vol 9 ◽  
Author(s):  
Shibin Luo ◽  
Zhichao Miao ◽  
Jian Liu ◽  
Jiawen Song ◽  
Wenxiong Xi ◽  
...  
Keyword(s):  
Porous Media ◽  
Heat Conduction ◽  
Double Layer ◽  
Cooling System ◽  
Convection Heat Transfer ◽  
Leading Edge ◽  
Hypersonic Vehicle ◽  
Transpiration Cooling ◽  
Stagnation Region ◽  
Operation Conditions

As a promising and efficient active cooling method, double layer transpiration cooling is introduced into the design of the cooling system in the leading edge of a hypersonic vehicle. The physical model is built combined with hypersonic transpiration cooling, film cooling, heat conduction, porous media heat conduction and convection heat transfer. In addition, effects of different kinds of coolants are considered to reveal cooling mechanisms in different operation conditions. A comprehensive turbulence model validation and mesh independence study are provided. Flow characteristics caused by flow impingement, separation, transition and interaction with the cooling flows are displayed and analyzed in the work. When different kinds of coolants supplied at the same mass flow rate, the coolants with low densities, i.e., H2 and He, have the lowest peak temperature compared with the coolants with large densities, i.e., N2 and CO2. The coolants with low densities have a large ejecting velocity which provides large kinetic energy to penetrate deeply in the porous media. In addition, when the ejecting velocity is large enough, a recirculation is formed in front of the leading edge and pushes the high temperature region located in stagnation region away from the leading edge. However, when the coolants are ejected at the same velocity, the coolants with large densities exhibit better cooling performance.

123 Numerical Analysis of Flow in Linear Turbine Cascades With Transpiration Cooling

2012 ◽  
Vol 2012.47 (0) ◽  
pp. 52-53
Author(s):  
Tetsuya KANNO ◽  
Tomoya TAKANASHI ◽  
Yasushi Miyazaki ◽  
Hoshio TSUJITA
Keyword(s):  
Numerical Analysis ◽  
Transpiration Cooling ◽  
Turbine Cascades

Numerical Analysis of Flow-Induced Vibration of Large Diameter Pipe With Short Elbow

2017 ◽  
Author(s):  
Shigeru Takaya ◽  
Tatsuya Fujisaki ◽  
Masaaki Tanaka
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Fast Reactor ◽  
Pressure Fluctuation ◽  
Cooling System ◽  
Large Diameter ◽  
Recirculation Region ◽  
Flow Induced Vibration ◽  
Scaled Model ◽  
Energy Agency

Japan Atomic Energy Agency is now conducting design study and R&D of an advanced loop-type sodium cooled fast reactor. The cooling system is planned to be simplified by employing a two-loop configuration and shortened piping with less elbows than a prototype fast reactor in Japan, Monju, in order to reduce construction costs and enhance economic performance. The design, however, increases flow velocity in the hot-leg piping and induces large flow turbulence around elbows. Therefore, flow-induced vibration (FIV) of a hot-leg piping is one of main concerns in the design. Numerical simulation is a useful method to deal with such a complex phenomenon. We have been developing numerical analysis models of the hot-leg piping using Unsteady Reynolds Averaged Navier-Stokes simulation with Reynolds stress model. In this study, numerical simulation of a 1/3 scaled-model of the hot-leg piping was conducted. The results such as velocity profiles and power spectral densities (PSD) of pressure fluctuations were compared with experiment ones. The simulated PSD of pressure fluctuation at the recirculation region agreed well with the experiment, but it was found some underestimation at other parts, especially in relatively high frequency range. Eigenvalue vibration analysis was also conducted using a finite element method. Then, stress induced by FIV was evaluated using pressure fluctuation data calculated by URANS simulation. The calculated stress generally agrees well the measurement values, which indicates the importance of precise evaluation of the PSD of pressure fluctuation at the recirculation region for evaluation of FIV of the hot-leg piping with a short elbow.

Energy Balance in Al-Co Open-Celled Foam of Transpiration Cooling

2014 ◽  
Vol 575 ◽  
pp. 41-45 ◽  
Author(s):  
Bundit Krittacom ◽  
Pipatana Amatachaya ◽  
Ratipat Sangchot
Keyword(s):  
Heat Transfer ◽  
Energy Balance ◽  
Cooling System ◽  
Solid Phase ◽  
Porous Plate ◽  
Heat Radiation ◽  
Transpiration Cooling ◽  
One Dimensional ◽  
Energy Of Interaction ◽  
Two Phases

Numerical model of one-dimensional steady-state on Alumina-Cordierite (Al-Co) open-celled foam using in transpiration cooling system have been conducted to investigate the local energy balance (LEB) of gas and solid phase within porous plate. Physical properties, i.e., porosity (f), pores per inch (PPI) and thickness (x), of Al-Co open-cellular porous material were 0.87, 13 and 0.103 m, respectively. Two equations of the conservative energy consisting of the gas and solid phase were analyzed. From study, it was found that heat convection (HVF) balanced with heat transfer between two phases/ energy of interaction (INT) for the gas phase case. In the solid phase, heat transfer between two phases (INT) tended to offset heat radiation (HRS). Remarkably, heat conduction of both phases (HDF and HDS) was not effected to the present cooling system. Thus, characteristic of fluid flow effecting by HVF and heat transfer governed from HRS was strongly efficient to transpiration cooling system.

Properties and Application of Oriented Porous SiC as Transpiration Cooling Materials

2007 ◽  
Vol 336-338 ◽  
pp. 1109-1112 ◽  
Author(s):  
Jie Tang ◽  
Yu Feng Chen ◽  
Ji Guo Sun ◽  
Hua Wang ◽  
Hai Lin Liu ◽  
...  
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Cooling System ◽  
Casting Process ◽  
Solid Loading ◽  
Transpiration Cooling ◽  
Rocket Engines ◽  
Intrinsic Permeability ◽  
Sic Ceramics ◽  
Porous Sic

This paper describes the fabrication of porous reaction-bonded SiC ceramics with radial directed pores and the application of these materials to transpiration cooling system of rocket engines. A special mold is designed for freeze-casting process to prepare SiC cylinders with radial directed pores. Green bodies with well-oriented pore structure are obtained from slurry with solid loading up to 47vol%. The pore size is in the level of several tens micron. Green bodies with various porosities are infiltrated with different amount of liquid Si. The intrinsic permeability of each sample is measured with air as flowing media. It is concluded that permeability has relationship with not only the porosity but also the pore structure of samples.

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