Modelling vaporous cavitation on fluid transients
نویسنده
چکیده
A comprehensive study of the problem of modelling vaporous cavitation in transmission lines is presented. The two-phase homogeneous equilibrium vaporous cavitation model which has been developed is compared with the conventional column separation model. The latter predicts unrealistically high pressure spikes because of a conflict arising from the prediction of negative cavity sizes if the pressure is not permitted to fall below the vapour pressure, or the prediction of negative absolute pressures if the cavity size remains positive. This is verified by a comparison of predictions with previously published experimental results on upstream, midstream and downstream cavitation. The new model has been extended to include frequency-dependent friction. The characteristics predicted by the frequency-dependent friction model show close correspondence with experimental data. q 2003 Elsevier Science Ltd. All rights reserved.
منابع مشابه
Discrete vapour cavity model with efficient and accurate convolution type unsteady friction term
This paper presents experimental data and numerical simulations of transient vaporous cavitation events generated by a downstream fast valve closure in a pipeline. The experimental apparatus comprises a 37.2 m long constant-sloping pipe of 22.1 mm internal diameter connecting two pressurized tanks. The simulation results show that improper selection of the weighting function in the convolution-...
متن کاملPhysical Modelling of Self-Aeration in a Cavitating Sudden PIPE Expansion Flow
Sudden pipe expansions have been known as efficient hydraulic energy dissipaters for a long time. The complex phenomenon of flow separation and velocity discontinuity at the interface of incoming jet and the recirculation flow, results in intensive shear and tensile rupture of the fluid and the associated destructive phenomenon of cavitation. This paper focuses on aeration in sudden pipe expans...
متن کاملEffect of Drying and Exposure to Vaporous Hydrogen Peroxide on the Inactivation of Highly Pathogenic Avian Influenza (H5N1) on Non-porous Surfaces
This study demonstrated the combined effect of drying and vaporous hydrogen peroxide exposure on inactivating highly pathogenic avian influenza (H5N1) on the non-porous materials glass, Hypalon ® rubber glove, and stainless steel. Approximately 7.7 log10 TCID50 (median 50% tissue culture infectious dose)/mL of A/Vietnam/1203/2004 H5N1 in allantoic fluid was dried on coupons of each type of test...
متن کاملNumerical Simulation of Cavitation in Mixed Flow Pump
The purpose of this study is to investigate the performance and three-dimensional behavior of the flow in a mixed flow pump and the way cavitation phenomenon is affected by different parameters such as fluid temperature, pump speed and flow rate. Computational fluid dynamic software FLUENT 6.3 was utilized to simulate the whole flow field of the pump. RNG k-ε model combined with standard wall f...
متن کاملNumerical Solution for Gate Induced Vibration Due to Under Flow Cavitation
Among the many force s to which hydraulic structures are exposed to, the forces induced by cavitation incident are of typical hydrodynamic unknown forces. The aim of this study is to define these forces as coupled fluid-structure interaction under two dynamic effects. The first dynamic effect which incorporates facilities for dealing with cavitation fluid is based on the appearance and bursting...
متن کامل