Numerical investigation of oil injection in a Roots blower operated as expander

International Conference on Compressors and their Systems 2019

Casari, Nicola^1 ; Fadiga, Ettore^1 ; Pinelli, Michele^1 ; Suman, Alessio^1 ; Kovacevic, Ahmed^2 ; Rane, Sham^3 ; Ziviani, Davide^4

University of Ferrara, via Saragat 1, Ferrara

44122, Italy^1

University of London, Northampton Square, London

EC1V 0HB, United Kingdom^2

Department of Engineering Science, University of Oxford, Osney Mead Industrial Estate, OX2 OES, Oxford, United Kingdom^3

Ray W. Herrick Laboratories, Purdue University, 177 S Russell Street, West Lafayette

IN

47907-2099, United States^4

关键词: Actual operation;    Computation fluid dynamics;    Integrated tools;    Numerical investigations;    Organic rankine cycles (ORCs);    Positive displacement;    Vapor compression refrigeration system;    Working chambers;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/604/1/012075/pdf
DOI  :  10.1088/1757-899X/604/1/012075

来源: IOP

【 摘 要 】

The adoption of positive displacement machines as expanders in Organic Rankine Cycles (ORCs) is increasingly common, especially in the low to medium power range. At the same time, these devices often serve as compressor in Vapor-Compression Refrigeration Systems. In both cases, the application of Computation Fluid Dynamics (CFD) to optimize such machines has become an integrated tool in the design process. As a consequence, several challenges associated with the numerical simulation have to be taken into account. For example, the modeling of the gap represents a challenge for the stability of the numerical analysis. The dynamic of the process, combined with deformations of the clearances and of the working chamber has to be considered with extra care. To raise the efficiency of the machine, oil is typically injected. Its numerical modeling imply an extra challenge in the simulation of the actual operation of the machine. The present work is mainly focused on the multi-phase nature of the flow, with a particular analysis of the lubricant oil injected. In this work, a two-lobe Roots blower operated as expander has been simulated with the open-source software OpenFOAM-v1812, using the SCORG-V5.2.2. This analysis highlights the areas that are affected the most by the oil presence in order to highlight the sealing effect it provides.