International Journal of Heat and Mass Transfer, Vol.51, No.5-6, 1049-1060, 2008
A simplistic model to study the influence of film cooling on low temperature hot corrosion rate in coal gas/syngas fired gas turbines
The present paper is an attempt to establish an analytical study of low temperature hot corrosion (LTHC) in the context of high temperature turbines using coal gas or syngas with trace amount of sulfur in the fuel. LTHC in the presence of film cooling is explored using a simple analytical approach and heat and mass transfer analogy with film cooling air temperatures from 450 degrees C to 550 degrees C, hot gas stream temperature of 1425 degrees C and 0.5% of sulfur concentration in the fuel. For all the cooling air temperatures studied here, film cooling augments corrosion when the mainstream velocity is high. However, reduction in the mainstream velocity results in the suppression of corrosion after employing film cooling. A sharp peak in corrosion rate close to the cooling hole (<10s) is also seen. As the base super alloy is vulnerable to hot corrosion in this region, designers should consider the high corrosion rate seriously. The present model provides a simple baseline prediction methodology and sets direction for optimization needs. (C) 2007 Elsevier Ltd. All rights reserved.