In this paper an experimental study was performed for relation between two-phase pressure drop and flow distribution in compact heat exchanger using small diameter tubes. We performed the experimental study in non-heating mode. A test section was consisted of the horizontal header (circular tube: φ 5 mm × 80 mm) and 10 upward circular channels (φ 1.5 mm × 850 mm) using acrylic tube. Three different types of tube insertion depth were tested for the mass flux and inlet quality ranging from of 50–200 kg/m2s and 0.1–0.3, respectively. Air and water were used as the test fluids. Two-phase pressure drop of each channel and three type of distribution header was measured. As whole, single-phase and two-phase, pressure drop in rear channel is found to be lower than that in front channel. In conclusion, we can claim that principle of distribution is almost same pressure drop in each channel. Comparing pressure drop in branch tube with correlation equation, it was found that in single-phase flow, experimental value was 10% lower than Hagen-Poiseuille, Blasius equation (Eq. 40) in two-phase flow.
