Two-phase pressure drop in a helical coil flow boiling system

The objective of the present work is to study the two-phase pressure drop in helical coils. Literature on the two-phase pressure drop in a helical coil suggests the complexity in flow boiling inside a helical coil due to secondary flow. Most of correlations reported in the literature on the two-phase pressure drop in a helical coil are limited to a specific operating range. No general correlation is available for a helical coil which is applicable for all fluids. In the present study, an experimental databank collected containing a total of 832 data points includes the data from the present study and from the literature. The data includes diabatic pressure drop of two fluids namely water and R123. Data covers a range of parameters namely a mass flux of 120-2058kg/m(2)s, a heat flux of 18-2831kW/m(2), an exit quality of 0.03-1, a density ratio of 32-1404 and a coil to tube diameter ratio of 14-58. The databank is compared with eighteen empirical correlations which include well referred correlations of straight tubes and the available correlations of helical coils. The straight tube correlations are not working well for the present data set. The helical coil correlations work reasonably well for the present databank. A correlation is suggested to predict the two-phase pressure drop in helical coils. The present study suggests that the influence of a helical coil is completely included in the single phase pressure drop correlation for helical coils.