Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 53 Issue 3 (Special Issue) 2021 05 22 Modeling and parametric analysis of two-phase fluid stability in boiling process in a thermal channel Modeling and parametric analysis of two-phase fluid stability in boiling process in a thermal channel 1861 1882 3876 10.22060/mej.2020.17249.6550 FA Mohammad Reza Shah Nazari associate prof./ Mechanical faculty/K.N.Toosi university of technology Ashkan Amjadi Golpayegani K.N.Toosi University of technology Ali Saberi mechanial faculty, K.N.TOOSI UNIVERSITY OF TECHNOLOGY Journal Article 2019 10 20 In this paper, analysis of two-phase flow instability in a boiling process is investigated and a simple and comprehensive model is modified to express pressure drop. The defined model and nondimensional numbers give a comprehensive sight of different parameters' effect on the oscillations. By using Lyapunov stability analysis, conditions in which instability occurs are identified. The effect of parameters on the diagram of pressure drop versus mass flow rate are investigated and the existence of extremum is discussed. The oscillation form varies according to the value of the basic oscillation damping parameter from an elliptical orbit to a quadrilateral, corresponding to the pressure drop curve. The characteristics of their oscillation circuit, amplitude, and frequency were discussed analytically in terms of problem quantities. In addition, by nonlinear analysis, variation of the oscillation period is examined and its relation to the parameter of systems is investigated. In high operating pressure, the oscillation period is a function of fluid density and geometry of the thermal channel. Also for high compressible volumes, this characteristic increases with decreasing input mass flow rate in an unstable condition. In this paper, analysis of two-phase flow instability in a boiling process is investigated and a simple and comprehensive model is modified to express pressure drop. The defined model and nondimensional numbers give a comprehensive sight of different parameters' effect on the oscillations. By using Lyapunov stability analysis, conditions in which instability occurs are identified. The effect of parameters on the diagram of pressure drop versus mass flow rate are investigated and the existence of extremum is discussed. The oscillation form varies according to the value of the basic oscillation damping parameter from an elliptical orbit to a quadrilateral, corresponding to the pressure drop curve. The characteristics of their oscillation circuit, amplitude, and frequency were discussed analytically in terms of problem quantities. In addition, by nonlinear analysis, variation of the oscillation period is examined and its relation to the parameter of systems is investigated. In high operating pressure, the oscillation period is a function of fluid density and geometry of the thermal channel. Also for high compressible volumes, this characteristic increases with decreasing input mass flow rate in an unstable condition. https://mej.aut.ac.ir/article_3876_834a3bd235bca0caa53141f2ebc30438.pdf