Boundary conditions for a forced transpiration cooling system

1984 ◽  
Vol 47 (4) ◽  
pp. 1170-1176 ◽  
Author(s):  
V. A. Maiorov
Keyword(s):  
Boundary Conditions ◽  
Cooling System ◽  
Transpiration Cooling

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.

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.

Gas-Bubble Dynamics with Unstable Operation of a Transpiration Cooling System

2002 ◽  
Vol 33 (5-6) ◽  
pp. 8
Author(s):  
B. V. Kichatov ◽  
V. M. Polyaev ◽  
S. V. Runovskii
Keyword(s):  
Bubble Dynamics ◽  
Cooling System ◽  
Transpiration Cooling ◽  
Gas Bubble

Discussion of Boundary Conditions of Transpiration Cooling Problems Using Analytical Solution of LTNE Model

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Jianhua Wang ◽  
Junxiang Shi
Keyword(s):  
Temperature Field ◽  
Analytical Solution ◽  
Boundary Conditions ◽  
Coolant Temperature ◽  
Transpiration Cooling ◽  
Dimensional Problem ◽  
Gas Temperature ◽  
One Dimensional ◽  
Hot Gas ◽  
Hot Surface

To compare five kinds of different boundary conditions (BCs), an analytical solution of a steady and one-dimensional problem of transpiration cooling described by a local thermal nonequilibrium (LTNE) model is presented in this work. The influence of the five BCs on temperature field and thermal effectiveness is discussed using the analytical solution. Two physical criteria, if the analytical solution of coolant temperature may be higher than hot gas temperature at steady state and if the variation trend of thermal effectiveness with coolant mass flow rate at hot surface is reasonable, are used to estimate the five BCs. Through the discussions, it is confirmed which BCs at all conditions are usable, which BCs under certain conditions are usable, and which BCs are thoroughly unreasonable.

Boundary Conditions for Numerical Simulation of Diesel Water Jacket

2011 ◽  
Vol 291-294 ◽  
pp. 2328-2333
Author(s):  
Zhe Xin ◽  
Shun Xi Wang ◽  
Ke Peng Zhang ◽  
Zhao Jing Li ◽  
Feng Yun
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Diesel Engine ◽  
Boundary Conditions ◽  
Transfer Coefficient ◽  
Cooling System ◽  
Convective Heat Transfer Coefficient ◽  
Water Jacket ◽  
Fluid Coupling ◽  
Solid Fluid Coupling

In the research of flow and heat transfer of the diesel engine cooling system, the boundary condition determination was often a difficult problem. The paper calculated the flow velocity and convective heat transfer coefficient respectively for a six-cylinder diesel engine under different boundary conditions which including the water jacket wall as adiabatic condition, average temperature condition, and the boundary conditions from the solid-fluid coupling calculating. And the calculated values of the jacket wall temperatures were compared with that of test. The results showed that the simulation with solid-fluid coupling boundary conditions had better precision. Based on the research, an improved structure design was conducted for the six-cylinder diesel engine, the results of simulation showed that the average flow speed at the internal surface of water jacket could reach up to 0.5m/s, the flow symmetry in each jacket got improved, and the convective heat transfer coefficient could reach more than 2000 W/m2·K. The improved cooling system can meet the design requirements.

Sign in / Sign up

Export Citation Format

Share Document