Pressure Drop Characteristics of Flow Boiling in Narrow Rectangular Channel

Pressure drop is the earliest and the most extensive issue in the research of two phase flow. Due to the influence of various factors on two phase flow pressure drop, there is no accurate and general correlation on this issue yet. In this paper, pressure drop characteristics of flow boiling were studied in a single vertical narrow rectangular channel with cross-section of 47 mm by 1.8 mm using water as working fluid. Subcooled flow boiling was experimentally investigated. The experimental conditions included inlet subcooling (2°C∼18°C), mass flow rate (222.3∼457.4 kg.m²s⁻¹) and heat flux (113.6∼270.5 kW/m²). The influence of these parameters on the characteristics of flow boiling pressure drop has been investigated. The experimental results show that the conventional correlations failed to predict the two-phase flow pressure drop in this narrow rectangular channel. According to experiment results, a modified Chisholm correlation was proposed, and the new correlation gave more accurate predictions of the pressure drop.