Implementation of a transpiration velocity based cavitation model within a RANSE solver

Reciprocating piston pumps are widely used in various fields, such as automobiles, ships, aviation, and engineering machinery. Conventional reciprocating piston pump distributing flow (RPPDF) systems have the disadvantages of a loose structure and low volumetric efficiency, as well as affected positively by the operating frequency. In this paper, a novel rotating-sleeve distributing flow (RSDF) system is presented for bridging these drawbacks, as well as structurally improved to overcome the inoperable and challenging problems in oil intake and discharge found in the experiment. Moreover, the Singhal cavitation model specifically for the RSDF system and four-cam groove profiles (CGPs) is established. To find the most suitable CGP to reduce the RSDF’s cavitation, the cavitation of the RSDF system was investigated, combining with simulations by taking into account the gap among the rotating sleeve, the pump chamber, and experiments on four presented CGPs. Simulation results based on vapor volume fraction, cavitation ratio, and volumetric efficiency show that the linear profile’s cavitation is the weakest. Finally, the correctness of the simulation is verified through orthogonal experiments. This research is of great significance to the further development of the RSDF system; more important, it has great potential to promote the reform of the RPPDF method.

Download Full-text

Mass-conserving cavitation model for dynamical lubrication problems. Part II: Numerical analysis

Mathematics and Computers in Simulation ◽

10.1016/j.matcom.2014.11.024 ◽

2015 ◽

Vol 118 ◽

pp. 146-162 ◽

Cited By ~ 7

Author(s):

Gustavo C. Buscaglia ◽

Mohamed El Alaoui Talibi ◽

Mohammed Jai

Keyword(s):

Numerical Analysis ◽

Cavitation Model

Download Full-text

New Development of a Gas Cavitation Model for Evaluation of Drag Torque Characteristics in Disengaged Wet Clutches

SAE International Journal of Engines ◽

10.4271/2016-01-1137 ◽

2016 ◽

Vol 9 (3) ◽

pp. 1910-1915 ◽

Cited By ~ 10

Author(s):

Shahjada A. Pahlovy ◽

Syeda F. Mahmud ◽

Masamitsu Kubota ◽

Makoto Ogawa ◽

Norio Takakura

Keyword(s):

Drag Torque ◽

Cavitation Model ◽

New Development

Download Full-text

On the choice of CFD codes in the design process of planing sailing yachts

10.5957/csys-2009-004 ◽

2009 ◽

Author(s):

Jérémie Raymond ◽

Jean-Marie Finot ◽

Jean-Michel Kobus ◽

Gérard Delhommeau ◽

Patrick Queutey ◽

...

Keyword(s):

Free Surface ◽

Design Process ◽

Finite Differences ◽

Potential Flow ◽

Surface Condition ◽

Cpu Time ◽

Free Surface Condition ◽

Finite Differences Method ◽

Non Linear ◽

Ranse Solver

The discussion is based on results gathered during the first two years of a 3 years research program for the benefits of Groupe Finot-Conq, Naval Architects. The introduction presents the objectives of the program: Setting up a practical method using numerical and experimental available tools to design fast planing sailing yachts. The aim of this paper is to compare advantages and disadvantages of four different kinds of CFD codes which are linear and non-linear potential flow approach, RANSE solver using finite differences method and RANSE solver using volume of fluid method. The Fluid Mechanics Laboratory of the Ecole Centrale de Nantes (France) has developed those three approaches so those homemade codes will be used for this study. The first one is REVA, a potential flow code with a linearised free surface condition. ICARE is a RANSE solver using finite differences method with a non linear free surface condition. It is extensively used for industrial projects as for sailing yachts projects (ACC for example). ISIS-CFD is a RANSE solver using finite volume method to build the spatial discretization of the transport equations with unstructured mesh. The latter is able to compute sprays for fast planing ships but is also the slower in terms of CPU time. In addition, we had the opportunity to test FS-FLOW which is a potential flow code with a non linear free surface condition distributed by FRIENDSHIP CONSULTING. Numerical results for the four codes are compared with the other codes' results as with tank tests data. Those tank tests were made using captive model test technique on two Open60' models. Reasons of the choice of the captive model technique are explained and experimental procedures are briefly described. Comparisons between codes are mainly based on the easiness of use, the cost in CPU time and the confidence we can have in the results as a function of the boat speed. Flow visualizations, pressure maps, free surface deformation are shown and compared. Analysis of local quantities integrated or by zone is also presented. Results are analyzed focusing on the ability of each code to represent flow dynamics for every speed with a special attention to high speeds. The practical question raised is to know which kind of answers each code can bring in terms of tendencies evaluation or sensitivity to hull geometry modifications. The main goal is to be able to judge if those codes are able to make reliable and consistent comparisons of different designs. Conclusion is that none of the codes is perfect and gather all the advantages. It is still difficult to propose a definitive methodology to estimate hydrodynamic performances at every speed and at every stage of the design process. Knowing each code limitations, it appears more coherent to use each of them at different stages of the design process: the quickest and less reliable to understand the main tendencies and the longest and more precise to validate the final options.

Download Full-text