Mechanical Power Engineering Department, Faculty of Engineering, Menoufyia University, Shebin El-Kom, Egypt
Cavitation breakdown at various liquid temperatures is one of the major problems encountered in the operations of centrifugal pumps. There are a number of practical cases where the pumps operate at high temperature or near the saturation temperature of the liquid. A detailed understanding of the factors affecting the breakdown of cavitation is essential for accurate performance prediction and design. The purpose of this paper is to present results of a cavitation breakdown investigation which are both experimental and theoretical. The present model based on Rayleigh-Plesset expression for bubble dynamics. The predicted model includes many important parameters controlling the cavitation breakdown such as bubble dynamics, flow rate, rotational speed, temperature and thermodynamics properties of water and the gas pressure inside the cavity. The present model has been tested against extensive present and earlier published experimental results in centrifugal pumps at various operating water temperatures and operating conditions. The comparison between the predicted breakdown blade cavitation number with the present and previous published experimental results showed a surprisingly good agreement. This agreement means that the roles played by many important parameters are consistent with the present model. Therefore, the present model represents an addition to knowledge in this aspect which could help the centrifugal pump user and designer to predict the breakdown cavitation performance at various operating conditions.