An experimental study on heat/mass transfer and pressure drop characteristics for arrays of nonuniform plate length positioned obliquely to the flow direction

In this paper, heat/mass transfer and pressure drop characteristics for arrays of nonuniform plate length, aligned at an angle of 25 deg to the flow direction, are investigated experimentally via a naphthalene sublimation technique. The measurements of cyclic average Sherwood numbers and friction factors in the fully developed regime are conducted for nine geometric configurations. The following parameter ranges are studied: length ratio of successive plates 1.5-2.5; ratio of the transverse pitch to the longitudinal pitch 0.381-0.8, and Reynolds number based on short plate length 1.98 × 10² to 1.66 × 10³. Comparisons with the results for arrays with uniform plate length are conducted. Two constraints are used, identical pumping power and identical pressure drop. It is found that for most cases studied, the thermal performance of the array with a nonuniform plate length is better than that of the array with a uniform plate length.