Steady State Transpiration Cooling System in Ni-Cr Open-Cellular Porous Plate

The steady-state temperature for one-dimensional transpiration cooling system has been conducted experimentally and numerically to investigate the heat transfer characteristics of combined convection and radiation. The Nickel –Chrome (Ni-Cr) open-cellular porous material having porosity of 0.93 and pores per inch (PPI) of 21.5 was examined. The upper surface of porous plate was heated by the heat flux of incoming radiation varying from 7.7 - 16.6 kW/m2 whereas air injection velocity fed into the lower surface was varied from 0.36 - 1.27 m/s, and was then rearranged as Reynolds number (Re). For the report of the results in the present study, two efficiencies including of temperature and conversion efficiency were presented. Temperature efficiency indicating how close the mean temperature of a porous heat plate to that of inlet air, and increased rapidly with the air injection velocity (Re). It was then saturated and had a constant value at Re higher than 10. The conversion efficiency, which was regarded as the ability of porous material in transferring energy by convection after absorbed from heat radiation, decreased with increasing of the heat flux and air injection velocity. In addition, it was then asymptotic to a constant value at the Re higher than 10. The numerical predictions also agreed with experimental data very well.

• P. Amatachaya
• P. Khantikomol
• R. Sangchot
• B. Krittacom

• Convection
• open-cellular
• radiation
• transpiration cooling
• Reynolds number.

[1] Grootenhuis, P., "The mechanism and application of effusion cooling",
Journal of the Royal Aeronautic Society, vol. 63, pp. 73 - 89, Feb.
1959.
[2] Choi, S.H., Scotti, S.J., Song, K.D. and Ries, H., "Transpiring cooling
of a scram-jet engine combustion chamber", NASA AIAAA-97-2576,
1997.
[3] Glass, D.E., Dilley A.D. and Kelly, H.N., "Numerical analysis of
convection/transpiration cooling", AIAA J Spacecraft Rockets, vol. 38
no.1, pp. 15-20, 2001.
[4] Bayley, F.J. and Turner, A.B., "The heat transfer performance of porous
gas turbine blades", Aeronautical J, vol. 72 (696), pp. 1087-1094,
1968.
[5] Bayley, F.J., "Transpiration cooled turbines", Proc. Instn. Mech.
Engineering, vol. 185, no. 69/71, pp. 943-956, 1970.
[6] Duwez, P. and Wheeler, H.L., "Experimental study of cooling by
injection of a fluid through a porous material", Journal of Aeronautical
Sciences, vol. 15, pp. 509 - 521, Sep. 1948.
[7] Andrews, G.E. and Asere, A., "Transpiration cooling of gas turbine
combustion chamber walls", Institute of Chemical Engineering
Symposium Series, vol. 86, pp.1047-1056, 1984.
[8] Fu, X., Viskanta, R. and Gore, J.P. "Measurement and correlation of
volumetric heat transfer coefficients", Experimental and Thermal and
Fluid Science, vol. 17, no.4, pp.285-293, Aug. 1998.
[9] Kubota, H., "Thermal response of a transpiration-cooled system in a
radiative and convective Environment", Transaction of the ASME:
Journal of Heat Transfer, vol. 99, pp. 628 - 633, Nov. 1977.
[10] Eckert, E.R.G. and Cho, H.H., "Transition from transpiration to film
cooling", Int J Heat Mass Transfer, vol. 37 (supplement 1), pp.3-8,
Mar. 1994.
[11] Wolfersdorf, J.V., "Effect of coolant side heat transfer on transpiration",
Heat Mass Transfer, vol. 41, pp.327-337, 2005.
[12] Andoh, Y.H., and Lips, B. "Prediction of porous walls thermal protection
by effusion or transpiration cooling. An analytical approach", Applied
Thermal Energy, vol. 23, no. 15, pp.1947-1958, Oct. 2003.
[13] Jiang, P.-X., Yu, L., Sun, J.-G., and Wang, J., "Experimental and
numerical investigation of convection heat transfer in transpiration
cooling", Applied Thermal Engineering, vol. 24, no. 8-9, pp.1271-1289,
Jun. 2004.
[14] Kamiuto, K. "Thermal characteristics of transpiration cooling system
using open-cellular porous materials in a radiative environment", Int. J.
Trans. Phenomena, vol. 7, pp. 58-96, 2005, pp.62-68.
[15] Krittacom, B., Studies on Thermal Characteristics of Open-Cellular
Porous Burners, Ph.D. Dissertation, Oita University, Japan, 2009.
[16] Kamiuto, K., Saito, S. and Ito, K., "Numerical model for combined
conductive and radiative heat transfer in annular packed beds,
Numerical Heat Transfer, Part A, vol. 23, pp.433-443, 1993.