The Adiabatic Film Effectiveness of the Double Wall with Inclined Multihole and Discrete-hole for Combustor Liner

The adiabatic wall film cooling effectiveness of double wall with impingement of cooling air through discrete-hole wall to the inclined multihole wall were investigated experimentally,on the basis of the heat-mass transfer analogy.The mass transfer measurements were conducted for film cooling mass flow ratios ranging from 0.5 to 2.0,different hole pitch-to-diameter ratios,and the spacing of double wall.Finally,the formulas for five different structures of double wall were fitted by the least square method according to the distribution of average lateral adiabatic wall film cooling effectiveness.The results of the investigation show that the adiabatic wall film cooling effectiveness is affected very little by the distance between the double wall for the same blowing ratio and the same geometry of the inclined multihole wall.But its distribution is determined mainly by the blowing ratio and the hole arrangement of the inclined multihole wall.The long rhombus hole arrangement of the inclined multihole wall is a better way in view of the adiabatic wall film cooling effectiveness.