Flow boiling characteristics of water in a horizontal tube under hypergravity environment

Test on flow boiling frictional pressure drop characteristics of water in a horizontal 1.8 mm inner diameter tube under different hypergravities were conducted by using a centrifugal acceleration machine on the ground.The test conditions were hypergravities of 1.00g-3.16g，mass fluxes of 230 and 330 $\mathrm{k}\mathrm{g}/({\mathrm{m}}^{\mathrm{2}}?\mathrm{s})$，heat fluxes of 102 and 141 kW/m²，and vapor qualities from 0.07 up to 0.58.The results showed that different hypergravities，vapor qualities，heat fluxes，and mass fluxes all had effect on the frictional pressure drops of water，and the frictional pressure drops decreased with increasing hypergravities slightly，and increased with increasing vapor qualities significantly.Moreover，the frictional pressure drops increased with increasing both mass flux and heat flux，and the effect of mass flux was more remarkable.The applicability to the test data of eight flow boiling frictional pressure drop correlations developed for normal gravity were evaluated，and the minimum mean absolute deviation and mean relative deviation were 7.8% and 6.9%，respectively，among the correlations.The flow patterns of normal gravity and hypergravity were simulated by using Fluent software because the flow patterns of flow boiling were affected by hypergravities significantly.The simulation results indicated that the effect of hypergravity on flow boiling gas-liquid separation was obvious.