Case study: Roots blower numerical mesh with conformal interface

Client: City, University of London | Website:

SCORGTM grid generator is using algebraic grid generation for distribution of boundary points on the interface between the two rotor domains. This example shows use of a conformal interface with vertex-to-vertex distribution of nodes at the interface between the two rotor domains. This type of boundary distribution is required by some CFD solvers such as Ansys Fluent and Star CCM+ for performing transient calculation and in other solvers such as PumpLinx and Ansys CFX it will help in faster calculation and achieving better numerical accuracy. This also helps in allowing additional physics to be included in the calculations such as liquid injection or solid fluid interaction.


The example shown here is for the rotor profile extracted from CAD models of the Roots blower which were imported in SCORGTM. The fully conformal numerical mesh with conformal interface between the rotors is directly supplied to the CFD solver where transient analysis was carried out with both single phase Air as ideal gas as well as the two phase ideal gas with water injection.


The single phase case with the conformal interface with a coupled pressure based CFD solver obtained converged solution in about 1/3 of the time required for the same solver with sliding interface.


The solution from multiphase case was obtained with both Euler-Euler and Euler-Lagrange methods. The difference in results achieved is very small.


Results presented in figures and videos show the distribution of pressure on the rotors and velocity vectors in the cross section passing through the suction and discharge ports.


Watch Video: Gas Temperature distribution


Watch Video: Water Volume Fraction distribution


The conformal vertex-to-vertex interface is being continually improved. The mesh for twin screw rotor will be presented in the separate gallery case.


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