Analysis of the Inner Fluid-Dynamics of Scroll Compressors and Comparison between CFD Numerical and Modelling Approaches

Abstract

Scroll compressors are widely adopted machines in both refrigeration systems and heat pumps. However, their efficiency is basically poor and constitutes the main bottleneck for improving the overall system performance. In fact, due to the complex machine fluid dynamics, scroll design is mainly based on theoretical and/or semi-empirical approaches. Designs strategies that do not guarantee an in-depth analysis of the machine behavior can be supplemented with a Computation Fluid Dynamics (CFD) approach. To this purpose, in the present work, the scroll compressor inner fluid dynamics is numerically analyzed in detail using two CFD software and two different modelling strategies for the axial gap. The analysis of the fluid evolution within the scroll wraps reveals unsteady phenomena developing during the suction and discharge phases, amplified by the axial clearance with negative impact on the main fluid flow (e.g., −13% of average mass flow rate for an axial gap of 30 μ) and on the scroll performance (e.g., +26% of average absorbed power for an axial gap of 30 μ). In terms of accuracy, the k-ε offers good performance on the estimation of average quantities but proves to be inadequate for capturing the complexity of the unsteady phenomena caused by the axial gap (e.g., −19% of the absorbed power in case of perfect tip seal). The need for considering specific geometric details in design procedures is highlighted, and guidelines on the choice of the most suitable numerical model are provided depending on the analysis needs.

CFD Analysis of a Two-Phase Fluid Flow Compressor

“…The average inlet and outlet mass flow rates, as well as the isentropic and volumetric efficiencies obtained numerically, are in good accordance with the results of a deterministic model (DM) available in the literature [3]. Besides, the distribution of pressure and velocity inside the compressor agrees qualitatively well with the results of numerical studies of scroll compressors available in the literature [4,5]. The high isentropic and volumetric efficiencies indicate that the investigated compressor type has been well-designed and is capable of efficiently compressing the refrigerant while delivering the desired mass flow rate at the specified pressure and temperature.…”

Analysis of Tangential Leakage Flow Characteristics in a Variable Diameter Dual Circular Arc Vortex Compressor

“…A vortex compressor is a type of fluid machinery that compresses gas by the eccentric rotation and translational motion of a vortex disk, driven by the main shaft, meshing with a static vortex disk [23]. During operation, several closed and symmetrical crescentshaped volumetric spaces are formed between the dynamic and static vortex disks.…”

Key Technologies and Application of Electric Scroll Compressors: A Review

“…The simulation outcomes offer valuable flow information, such as pressure distribution and flow rate, which can be utilized to enhance the design of similar systems. Cavazzini et al [55] conducted numerical simulations to investigate the internal fluid dynamics of a compressor, employing CFD software and various axial clearance modeling strategies. Zheng et al [56] conducted a study on the control method for tangential leakage.…”