A thermodynamic computational model analysis of a newly designed Tri-Rotor (T-R) volume air compressor

Abstract

A thermodynamic computational modelling (TCM) approach is developed to model and simulate thermodynamic processes of a newly designed rotary type air compressor named ‘tri-rotor (T-R) compressor’ using a Lattice-Boltzmann Method (LBM) based fluid flow solution, which is applied for the first time to a rotary compressor flow. With this method, which is combined with a Wall-Adapting Local Eddy-viscosity sub-grid scale stress (SGS) model (WALE), time-consuming classic fluid-domain meshing/re-meshing process is not required and a mesh deformation problem leading to numerical instability is overcome by generating a fixed Cartesian lattice. The proposed TCM approach here is expected to serve as a basis for transient simulations of rotating turbulent and highly compressible flow for accurate and more complete computational representation of an ideal, adiabatic compression process through pressure − rotational angle (P-Theta degree) and volume − rotational angle (V-Theta degree) diagrams. The designed compressor is comprised of three specifically shaped, simultaneously rotating rotors, which are well-positioned in a cylinder to draw and discharge air uninterruptedly through two-suction and two-discharge ports, respectively and achieves higher mass-flow rates with increasing rotational speed. A comparative study with different rotational speeds predicts that high isentropic efficiency ranging from 0.850 to 0.941 can be attained for the investigated rotational speed range without any compromise on mass flow rates and pressure ratios. A proof-of-concept experiment of a full-scale T-R compressor model is conducted to assess its operational feasibility and performance. It is found that the TCM approach reproduces comparable results to those obtained from the preliminary experimental studies.