New prediction of Murphree efficiency for distillation tray operating under entrainment condition

Abstract

A new empirical correlation has been presented for the effect of entrainment on distillation tray efficiency based on the results of numerical solution given by Lockett, et al. The calculated results are in good agreement with those of the numerical solution given by Lockett, et al. The average deviation is 1.14% and the maximum deviation is 4.76% for the ranges of 0 < P e 1000, 0.40 EOG 1.00, 0.5 λ0 3.0 and e0 0.3. In comparison with the correlation proposed by Bennett et al., the average and maximum deviations of E a MV are 2.17% and 20.49%, respectively. Nomenclature e0-entrainment fraction (e0 = E + /L0) E + -entrainment flow rate (kg·s −1 ) EOG-vapor phase point efficiency EMV-vapor phase tray efficiency in the absence of entrainment E a MV -vapor phase tray efficiency containing effect entrainment E a MV1 -calculated values of E a MV given by Lockett, et al. E a MV2 -calculated values of E a MV from (3) E a MV3 -calculated values of E a MV from (4) L0-flow rate of liquid on tray in the absence of entrainment (kg·s −1 ) m-slope of equilibrium line P e-Peclet number of liquid on tray V -vapor flow rate (kg·s −1 ) λ0-stripping factor (λ0 = mV L 0 )

Influence of tip clearance inclination on the performance of axial flow impeller in storage mode

“…By comparing and analyzing the results, the unstable hydraulic factors under over load conditions are obtained. Tang et al 15 applied the slotting technology to the impeller of axial flow pump and designed a new type of axial flow pump impeller. The hydraulic performance and flow field characteristics of the two impellers under different conditions are analyzed.…”