We are pleased to announce the release of TwinMesh 2024! For getting a download link please get in touch with us. Heere we have some information about the new features for you: New machine type: twin screw vacuum pumps Twin-screw vacuum pumps consist of rotors with very sharp edges and a high wrap angle that often increases towards the pressure side. In the TwinMesh 2024 release, some new features simplify the meshing process and allow the generation of high-quality meshes for twin-screw vacuum pumps. New post-smoothing type (TM2024) The new smoothing type in TwinMesh 2024 is mor ..read more

While development and simulation of screw compressors for heavy gases as air or refrigerants are quite usual, those for light gases, here especially hydrogen as future carrier of green energy, make high demands on internal clearance sizes, rotor profiles, and operating conditions to ensure high efficiency. This also poses a challenge for the numerical CFD simulation since reduced clearances, higher pressure ratios, and increased tip speeds require high-quality meshes, better spatial and temporal resolutions, and stable numerical models for high-speed flows. But numerical simulation is a cruc ..read more

The TwinMesh™ user group grows and grows and grows! We are thrilled to follow and support our customers on their way to improve and optimize their machines reaching the next level in design and performance. We also really appreciate to hear the great success stories from our new TwinMesh™ customers all over the world. From scientific papers over conference presentations, success stories and validation projects, we are really proud of the achievements done by extraordinary engineers. The TwinMesh™ team from CFX Berlin Software GmbH is happy to announce several new TwinMesh™ reference custo ..read more

This animation shows a conical rotary compressor with non-parallel variable pitch rotors that compresses air from 1 bar to 5 bar. Starting from an initialization without oil, 3 l/min oil are injected. The oil seals the radial gap between both rotors, and cools down the gas during compression so that air flow increases compared to dry-running compressor. This simulation resembles that described in [1], but shapes of inner and outer rotor and inlet and outlet parts are chosen freely in the same ranges. The shape of the conical rotary compressor is similar to a progressing cavity pump but with ..read more

The new release of TwinMesh, version 2024 coming in October 2023, allows the CFD simulation of more complex applications: Reed valves Reed valves are part of different positive displacement machines, e.g. scroll compressors or rolling piston compressors. Their inclusion in the CFD simulation via a coupled fluid-structure co-simulation, e.g. with Ansys Mechanical, is quite complex and increases the numerical effort substantially. We succeeded with a simplified approach by pre-simulating the reed valve dynamics in Ansys Mechanical to get tabulated return forces and oscillation frequencie ..read more

In this CFD simulation, a double flow / two-sided SRM screw compressor (in German: zweiflutiger Schraubenverdichter) has been setup with air at inlet pressure 1 bar, outlet pressure 6 bar and rotational speed of 12,333 rpm. The compressor is designed for a volume ratio of 3, i.e. it works in under-compression range here. When compression chamber opens towards pressure port, the chamber pressure is still below outlet pressure and it is filled with air from outlet region, i.e. backflow occurs. With further rotation, the gas is pushed towards the outlet. The main advantages of a two-sided comp ..read more

Abstract Increasing the efficiency of twin-screw machines is beneficial for gas compression and expansion applications. The researchers used a computation fluid dynamic approach to obtain the flow field and efficiency of a twin-screw machine that used R-134a as the working fluid. The leakage flow and sealing lines were obtained to study their geometrical effects during the compression and expansion process. The effects of the wrap angle (280°, 290°, and 300°) and pressure ratios on the compression efficiency were studied. During the compression process, the volumetric efficiency was more th ..read more

konstruktionspraxis is the leading trade journal for developers and designers in mechanical, apparatus and vehicle engineering, electrical engineering and other metal and plastics processing industries. konstruktionspraxis has been providing information on all phases of the design process for more than 30 years: from the design of the product to the selection of the appropriate material and the first prototypes to the necessary software and hardware. The selection of components and systems from connection, fluid and drive technology, automation and electrical engineering are also include ..read more

We participated in this year’s International Conference on Screw Machines and had a really good time. From September 7th to 8th experts from academic research and industry gathered in Dortmund to present and discuss the latest developments in screw compressor technology. Rainer Andres and Jan Hesse from CFX Berlin presented the topic “Investigation of Radial Gap Size Change under Load and the Impact on Performance for a Twin Screw Compressor using Numerical Simulation” This paper shows one workflow to adapt the deformation results of a structural simulation to a CFD setup. It starts wi ..read more

This animation shows a 4-6 screw compressor with SRM profiles; the rotor length is 168 mm, wrap angle of main rotor 300°, outer diameter of main rotor 102 mm, of gate rotor 101.2 mm, axis distance is 80 mm. The sizes of the radial gaps are 50 µm between rotors and casing, and 100 µm between both rotors. Axial gap sizes are 100 µm on suction and pressure side. The pressure port is designed for a built-in volume ratio of 2.2. The meshes for the fluid region around the rotors were pre-generated for each 2° rotation angle of the main rotor with TwinMesh. We used the outerfix approach, i.e. the ..read more