HEAT-TRANSFER INSIDE AND DOWNSTREAM OF CAVITIES USING TRANSIENT LIQUID-CRYSTAL METHOD

Local heat transfer coefficient distributions are investigated inside and downstream of various cavities on a flat surface, The effect of ca vity size, depth, and shape are studied using a transient liquid cryst al image method. Liquid crystals are sprayed on the test surface and a hot mainstream is imposed, suddenly causing a color change, The time of color change is obtained using an image processing system. An incre ase in cavity size for the same depth increases heat transfer coeffici ents on the test surface, An increase in cavity depth increases downst ream heat transfer coefficients. Five cavity shapes are studied to com pare local heat transfer behavior for the effect of various shapes.