Journal of Applied Mechanical Engineering

Unsteady bubbly cavitating nozzle flows

4^th International Conference and Exhibition on Mechanical & Aerospace Engineering

October 03-04, 2016 Orlando, USA

Zafer Baskaya

Istanbul Technical University, Turkey

Scientific Tracks Abstracts: J Appl Mech Eng

Abstract:

Unsteady quasi-one-dimensional and two-dimensional cavitating nozzle flows are considered using a homogeneous bubbly flow model. For quasi-one-dimensional nozzle flows, the system of model equations is reduced to two evolution equations for the flow speed and bubble radius and the initial and boundary value problems for the evolution equations are formulated. Results obtained for quasi-one dimensional nozzle flows capture the measured pressure losses due to cavitation, but they turn out to be insufficient in describing the two dimensional structures. For this reason, model equations for unsteady two-dimensional bubbly cavitating nozzle flows are considered and by suitable decoupling, they are reduced to evolution equations for the bubble radius and for the velocity field, the latter being determined by an integro-partial differential system for the unsteady acceleration. This integropartial differential system constitutes the fundamental equations for the evolution of the dilation and vorticity in two dimensional cavitating nozzle flows. The initial and boundary value problem of the evolution equations are then discussed and a method to integrate the equations is introduced. The numerical simulation of 2D cavitating nozzle flows is obtained by the CFD-Tool CATUM, which is based on an equilibrium phase transition model. Results obtained for a typical cavitation cycle show instantaneous high pressure pulses at instances of cloud collapses.

Biography :

Zafer Baskaya holds BSc in Mechanical Engineering and received PhD in 2011 from Faculty of Aeronautics and Astronautics of Istanbul Technical University (ITU). He carried out his early research in cavitation and bubble dynamics at ITU. He specializes in computational fluid dynamics and is also interested in applications of these numerical methods to various engineering problems, including Quasi-one-dimensional nozzle flows and unsteady cavitating flows. He has published papers in reputed journals and is a member of NFPA and ASME. He has also power industry experience that covers thermodynamic cycles, heat transfer and fluid flows. He is Chief Engineer at Unit Investment N V and has more than fifteen years of engineering and applications expertise in the power plants.

Email: zafer.baskaya@unit.com.tr