Cavitation damage tests of iron and steel have been carried out using two types of experimental facilities. One is a water tunnel system which presumably simulates the field conditions fairly closely and the other is a magnetostriction vibratory unit commonly used for accelerated cavitation erosion testing of metals. A comparison between water tunnel and vibratory tests shows a difference in mechanism of cavitation damage. Consequently, it has been concluded that the application of the test results obtained in a magnetostriction vibratory apparatus should be limited to provide rough data for the primary selection of proper materials to be used in the construction of hydraulic units and other industrial systems, unless damage is caused under similar conditions to that of the vibratory apparatus.
computing in turn the second and higher order perturbations of equations ( 6) through (8).These linear equations will then contain the radial velocity as well and, hence, the expanded theory could, for instance, be applied to the analysis of transients in distensible conduits by considering a parallel set of equations for the wall material.
tangent-gas approximation, this equation can be reduced to the Laplace equationand subscript m refers to the match state which is assigned experimentally, as discussed below.A similar procedure (with the added assumption of irrotational flow) can be followed to show that the velocity potential also satisfies the Laplace equation.The solution for the stream function and potential function which can be found by the method of singularities is, therefore, O(o) -id) = yu In 7T 7T
This paper develops a program for closed loop simulation of the transient behavior of a hydroelectric composite. The system modeling is comprehensive, including such factors as governor nonlinearities in mechanical compensation and servomotion. Special emphasis is given to conduit simulation in its elastic and frictional characteristics. The problem of friction is treated by appropriate attenuation of the traveling pressure wave. This point of view accounts for the phenomenon of regained head at decreased flows. The turbine characteristics are represented globally by means of polynomial approximation [1].
This paper describes an experimental investigation of two-phase, air-water nozzle flows including critical or choked flow. Five different nozzle geometries were used. The nozzles exhausted to atmospheric pressure from stagnation pressures of 16 to 55 psia. The quality (mass fraction of air flowing) ranged from 2 to 35 percent. A feature of the study was the injection system which was designed to minimize the entrainment of liquid into the gas phase. The data were found to be described within about 10 percent by modifying separated flow theory by a simple “blockage factor” correlation.
