The homogenous distribution of liquid and vapor over a plate surface is a key factor affecting the performance of brazed-plate heat exchangers in refrigeration and air-conditioning units. The two-phase flow and distribution over the plate surface were investigated with R410A fluid using computational fluid dynamics (CFD) simulation software. The distributions of pressure

velocity

and liquid volumetric fraction were comparatively analyzed. It was observed that the pressure

velocity

and liquid phase were distributed comparatively evenly for the herringbone plate. The velocity and liquid volumetric fraction along the plate centerline were slightly higher than those along the edges. However

for the dimpled plate

the velocities in the proximal zone were significantly higher than those in the distal zone

which is opposite to the distribution of liquid volumetric fraction. New methods called the mean two-phase flow deviation (MTFD) and mean liquid flow deviation (MLFD) at the nominal section were proposed to evaluate the maldistribution of fluid flow over the plate surface. The results indicated that the distribution and sideways flow were better for the herringbone plate than for the dimple plate. The MTFD values were 14.2% and 39.6%

and the MLFD values were 15.6% and 41.3% for the herringbone and dimple plates

respectively. It was determined that the bypass section existed in the flow direction for the round dimple plate

which led to poor sideways flow and earlier separation between the vapor and liquid. The proposed boomerang dimple plate pattern

similar to fish skin

can improve the two-phase flow distribution over the plate surface because it can reduce the size of the bypass section and generate vortices under a concave shape. The new geometry can enhance turbulence and promote the two-phase fluid to move sideways effectively. The MTFD and MLFD values were 7.6% and 8.9%

respectively.