CFD Analysis of Screw Compressor Using ANSYS: A Technical Paper

This technical paper presents a CFD analysis of a screw compressor using ANSYS software. The study focuses on simulating the compressor's performance, considering factors such as fluid dynamics, pressure, temperature, mass flow, and torque. The methodology involves creating models, setting up boundary conditions, and analyzing results to evaluate the compression process. The paper discusses the use of ANSYS CFX for the simulation, including the models used (total energy, solid CHT, and SST turbulence) and the boundary conditions applied (rotor speed, pressure, and temperature). The anticipated results include mass flow, torque, and power consumption, along with the computation time required. The analysis aims to visualize the compression process, evaluate chamber pressures, and compare different designs and operating points. The paper also includes references to relevant research in the field.

1Running head: CFD ANALYSIS OF SCREW COMPRESSOR USING ANSYS
CFD ANALYSIS OF SCREW COMPRESSOR USING ANSYS
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CFD ANALYSIS OF SCREW COMPRESSOR USING ANSYS
Introduction
Fluid dynamics is a study that is interesting and challenging in equal measure, since fields are every
where in the practical world, we are living in. Therefore, fluid dynamics is needed to study the flow of
fluid. There are three physical laws that can describe or solve the fluid flow, actually they are equations:
 Mass conservation: Continuity equation
 Momentum conservation: Momentum equation, the second law of Newton
 Energy conservation: Energy equation, the first law of thermodynamics
The philosophies described above shows that mass, momentum, and energy are steady constants in a
system that is closed.
We shall now describe what Computational Fluid Dynamics (CFD) is, which are numerical methods that
are applied to get approximate solutions for the heat transfer and fluid dynamics. CFD is an approach that
is very powerful that covers a vast range application that are industrial and non-industrial. Ansys CFD
and Twin-Mesh are used for; innovative and better designs to be able to understand the complex
techniques, and flexibility at cost reduction and a fast at virtual prototyping.
Methodology of simulating a screw compressor
A group of meshing helical screws rotors are contained in the screw compressor container/housing. There
are rotors which have their profile on the outer side of the pitch circle, these are called main rotors or
male rotors. Yet the ones with their profile into the pitch circle are known as the gate or female rotors.
The screw compressors have the main components in gears, and bearings among other components,
which needs to be lubricated by either isolating the shafts seals the applying the lubricants also at the
compressions chamber, and normal lubrication (Mathu, 2016).
Here, there shall be a description of the use of Ansys in solving problems, they are like the following:

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CFD ANALYSIS OF SCREW COMPRESSOR USING ANSYS
 Pre-analysis
 Geometry
 Mesh
 Physical setup
 Numerical solution
 Verification and validation
On ANSYS CFX, for 90 time making steps of 1O set up needs to be set as follows:
 The fluid shall be an ideal gas or air (dry compressor)
 The solid shall be steel
 Models to be created are:
 Total energy model that has got a good viscous dissipation and solid CHT
 SST model turbulence
 The rotor meshes, user Fortran, at a set run-time, deformation of the mesh for the solid rotation
The conditions of the boundary shall be:
 Male rotation speed of 12331rpm
 Side suction at 1 bar opening temperature of 27OC
 Side pressure opening at 3bar
 Boundary conditions that are not reflective
 Casing that is adiabatic with the exception of the shaft ends, which shall be at 70OC
The anticipated results shall be as follows, in terms of parameters;
Mass flow shall have an average of 0.13kg/s at a constant rate at the inlet, with a high fluctuation at the
outlet. A high torque at the male rotor, which shall be constant at an average of 18.2Nm, but a lower
female rotor torque averaging at 3.2Nm. Power consumed shall be 25.1kW, the computation time on

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CFD ANALYSIS OF SCREW COMPRESSOR USING ANSYS
ANSYS CFX-15.0.7 which has got a partitioning of MeTis shall be, 9 hours, with a memory capacity of
20GB for double precision solver (Spille-Kohoff, Hesse, & El Shorbagy, 2015).
The deep analysis of the screw compressors process
 Visualise the compression process by monitoring the pressures, temperatures, surface heat fluxes,
velocities, cross sections, and other parameters
 Evaluate the process of compression by monitoring the pressures of the chamber, mass flows,
power, gap flows, or torque
 Compare the different designs and the points of operation.
References

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CFD ANALYSIS OF SCREW COMPRESSOR USING ANSYS
Mathu, S. (2016). Finite Element Analysis of Screw Compressor. Conference:Ansys India
Conference 2016 (p. 1). Bangalore, India: Mahle Engine Components Indial Pvt Ltd.
Spille-Kohoff, A., Hesse, J., & El Shorbagy, A. (2015). CFD simulation of a screw compressor
including leakage flows and rotor heating. 9th International Conference on Compressors
and their systems (pp. 2-4). Berlin, Germany: CFX Berlin Software GmbH.