Comparison of empirical correlations and a two-equation predictive model for heat transfer to arbitrary arrays of single-phase impinging jets

This paper presents a partial review of single-phase experiments & correlations for heat transfer to an array of impinging jets and compares their ability to be predicted by a two-equation numerical model for an arbitrary array of jets. It is found that the two-equation numerical model can predict the average Nusselt number with a mean absolute error of 15.8% over the following ranges: Re < 105, 0.054 mm < dn < 8 mm, 0.05 kg/m2 s < mass flux < 7000 kg/m2 s, 0.25 < H/dn < 30, 1.8 < S/dn < 330, 1 < N < 397, with test fluids including air, water, R134a, FC40, and FC77. Using the predictive model, optimization is then carried out and a correlation is found for optimum jet spacing for square heaters with regular rectangular jet arrays.