Frictional pressure drop characteristics of steam-water two-phase flow in helically coiled tubes oriented with various axial angles

In this paper, an experimental and theoretical investigation on the characteristics of frictional pressure losses of steam-water two phase flow in helically coiled tubes was conducted in a wide range of system and flow parameters, which are as follows: system pressure p = 0.5-3.5 MPa; mass flow rate G=200-4300 kg/M²·S: heat flux q=0-580 kW·m^-2; exit mass quality x = -0.01-1.2. The angle between the central axis of helically coiled tube and horizontal line; θ=0°, +45°, 90°, -45°. The experimental results were analyzed and compared with some correlation and data proposed in previous literature. Based on Chen's correlation and our experimental data, a new revised correlation was proposed for the calculation of frictional pressure drop of gas liquid two-phase flow in helically coiled tubes oriented with various axial angles. A good agreement is arrived between the calculated values and experimental data.