Heat transfer and pressure drop characteristics of two-phase propane flow in shell side of LNG spiral wound heat exchanger

Abstract

For designing LNG spiral wound heat exchangers (SWHE), the boiling heat transfer and pressure drop characteristics of two-phase hydrocarbon refrigerant flowing downward at shell side should be known. In this study, an explosion-proof experimental rig was established for observing flow patterns and measuring heat transfer coefficients and pressure drops. The test section contained three-layer tube bundles to emulate the actual structure and flow conditions of a SWHE. Propane as one main component of shell-side refrigerant was used as the tested fluid. Through the experimental analysis, the influence laws of vapor quality, mass flux on flow pattern, heat transfer and pressure drop of propane are obtained. As the vapour quality increases, the heat transfer coefficient in the shell side of LNG SWHE initially increases and then decreases, representing a maximum at a vapour quality of 0.8~0.9. The flow patterns in the shell side of LNG SWHE present to be the column falling film flow, droplet falling film flow, shear flow, mist flow and gas flow as the vapour quality increases from 0.2 to 1.0.