Double wall cooling of an effusion plate with cross flow and impingement jet combination internal cooling: Comparisons of main flow contraction ratio effects

•Comparisons of hot-side effusion plate results are provided for a main flow passage with streamwise contraction ratios of CR = 1 and CR = 4.•Coolant supply arrangement for both CR values includes simultaneous use of cross flow and an impingement jet array.•Four different combination values of crossflow Reynolds number and impingement Reynolds number are tested for each CR value, associated with four different values of initial blowing ratio BR.•Variations of surface thermal protection are due to increased turbulent mixing and transport, different magnitudes of local blowing ratio, and the presence or absence of streamwise acceleration.•With main flow streamwise acceleration and CR = 4, decreases of heat transfer coefficients and adiabatic film effectiveness magnitudes occur, resulting in values which are significantly lower than when CR = 1.