SHEAR DRIVEN FILM FLOW BEHAVIOR AND CAVITATION STUDY (ACOUSTIC NOISE, LONG-CHAIN POLYMER ADDITIVE)

Two complicated important multiphase flow phenomena, shear driven thin film flow and cavitation were studied experimentally. Results were compared with available theoretical models.; The main objectives were to study (1) fluid property effects on shear driven films and interfacial wave structures and (2) the cavitation flow fields including the effects of long-chain polymer additives (AP-30 and Hec-H) on the cavitation erosion.; It is found that: (1) Film temperature on the turbine blade surface is equal to the local saturated steam temperature and is independent of water flow rate and water temperature in the reservoir. (2) Both high viscosity and long chain polymer additive stabilize the film flow, while low surface tension is destabilizing. (3) Mikielewicz's model can be used to predict the transition between rivulet and continuous film. (4) Ishii's model can be used to predict transition between continuous film and atomization film flow. (5) Von Karman's universal velocity profile can be used for modelling shear driven film flow. (6) The normal distribution function cannot be used to describe film thickness variation. (7) Long chain polymer additives (AP-30 and Hec-H) suppress cavitation erosion rate significantly. (8) Nondimensional cloud length can be represented by L/D = (1 - 0.942K)/K(0.805 - 0.0353K) where K is the cavitation number, D throat diameter for venturi tube, and L cavitation cloud length. The cavitation cloud oscillation frequency, determined by using a strobe light, increases as K increases. (9) Cavitation energy conversion efficiency is 9.6 x 10('-6) for aluminum 1100-0 from the venturi test. The results demonstrate that acoustic output can be used and should be used to predict the erosion rate for field machines in the future.