Internally geared screw machines with ported end plates

Read, Matthew; Smith, Ian K.; Stošić, Nikola

doi:10.1088/1757-899x/232/1/012058

Cited by 6 publications

(10 citation statements)

References 3 publications

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“…Details of the method of profile generation have previously been described by the authors [13]. This is summarised in Fig.…”

Section: Geometry Of Simple Rotor Profiles For Internally Geared Machmentioning

confidence: 99%

“…The internally-geared screw compressor with cycloidal rotor profiles has previously been analysed by the authors using a quasi-1D single chamber model approach to calculate the working chamber pressure and the resulting rotor torques and bearing forces [13,15]. This simplified analysis is based on the adiabatic compression of an ideal gas, neglecting leakage and pressure losses during filling or discharge, and allows an initial prediction of the pressure variation during the compression process.…”

Section: Modelling Of the Compression Processmentioning

confidence: 99%

“…12 This configuration presents challenges in achieving high accuracy in the manufacture of rotors using efficient and economical methods, and a simpler configuration using constant pitch and profile rotors with stationary porting has been proposed by the authors. 13,14 For compression applications, these gerotor profiles with helical twist have been shown to reduce the power transfer between rotors. 15 As with conventional twin-screw machines, low power transfer is expected to be an important factor in reducing friction and wear in the rotors, thereby improving durability and limiting the degradation of performance over time.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, the concept of conical internally-geared rotors with varying profile and nonparallel axes has been developed for compressor applications [12]. This configuration presents challenges in achieving high accuracy in the manufacture of rotors using efficient and economical methods, and a simpler configuration using constant pitch and profile rotors with stationary porting has been proposed by the authors [13,14]. For compression applications, these gerotor profiles with helical twist have been shown to reduce the power transfer between rotors [15].…”

mentioning

confidence: 99%

“…Ratio of net torque on the inner and outer rotors for a single cycle when N o = 4, ν = 0.8,Φ o = 0.2, 0.4, 0.6, 0.8 with v = 2 (black lines) and v = 5 (grey lines), based on an adiabatic compression cycle with no leakage or port pressure losses as described by Read et al[13].…”

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confidence: 99%

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Influence of rotor geometry on tip leakage and port flow areas in gerotor-type twin screw compressors

Read

Smith

Stošić

2020

Proceedings of the Institution of Mechanical Engineers, Part E:

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Conventional twin-screw compressors are positive displacement machines that form working chambers between two helical, parallel rotors and an outer casing. This study investigates an alternative configuration of rotors for compressor applications, in which the working chambers are formed by continuous contact between meshing inner an outer rotors. This is a similar configuration to gerotor machines, which are commonly used in fuel and oil pumping applications and as hydraulic motors. For compressor applications, the use of helical rotors with appropriate porting in a gerotor-type configuration has been identified as having potentially lower rotor contact forces and larger port areas than occur with non-helical rotors. This study investigates how key performance parameters of a gerotor-type screw compressor (volume, port flow areas and tip leakage areas) are influenced by the profile, dimensions and wrap angle of the rotors. The results of this geometric analysis are compared with a conventional twin-screw compressor, and suggest that the gerotor-type screw compressor can achieve higher axial port areas and lower tip leakage area over most of the compression cycle.

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“…Details of the method of profile generation have previously been described by the authors [13]. This is summarised in Fig.…”

Section: Geometry Of Simple Rotor Profiles For Internally Geared Machmentioning

confidence: 99%

Section: Modelling Of the Compression Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Influence of rotor geometry on tip leakage and port flow areas in gerotor-type twin screw compressors

Read

Smith

Stošić

2020

Proceedings of the Institution of Mechanical Engineers, Part E:

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Basic design procedure for an internally geared screw compressor

Read

2021

IOP Conf. Ser.: Mater. Sci. Eng.

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The internally geared gerotor type of positive displacement machine is widely used for pumping applications, but can also be used to achieve internal compression or expansion of a working fluid. A further development of this configuration is the application of helical twist to the inner and outer rotors. Previous studies have shown that this can decrease the power transferred between rotors, and increase the relative maximum flow areas at the inlet and discharge ports. There are possible benefits to this configuration when compared to conventional twin-screw machines, including reduced leakage area, stiffer rotors, and co-directional thermal expansion of rotors. However, no experimental data is currently available for this configuration, and optimising the geometry of the gerotor screw machine requires a detailed understanding of the porting, leakage flows and mechanical losses. An experimental programme is being conducted to investigate the influence of these factors on performance. This paper discusses preliminary results from geometrical analysis leading to a simple design procedure. The basic design of an internally geared air compressor is demonstrated, based on the operation characteristics of a conventional twin screw machine.

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Design and analysis of conical rotary compressor

Hoang

Noake

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Conical Rotary Compressor (CRC) is a screw type Positive Displacement Machine (PDM) consisting of one inner rotor rotating inside an outer rotor. The conical internal meshing rotors with the feature of variable pitch and rotor profile have an inherent capability to operation at high pressure ratio due to high built-in volume ratio and low leakage. CRC has potential to run in various applications such as Heating, Ventilation, and Air Conditioning (HVAC) system, vacuum pumps, and air compressors. The performance of the machine is heavily affected by rotor profile and rotor geometry. In this paper, non-parallel axis conical rotor is firstly introduced according to current successful design and manufacture practice, then parallel axis conical rotors are design based on meshing theory. Then, geometrical parameters such as meshing line length, cross section area, chamber volume and relative velocity are analysed. Finally, the experiments were conducted under different pressure ratio up to 26 and the volume flow rate, specific power, volumetric efficiency, and isentropic efficiency are compared. As a result of this study, CRC could maintain high level of volumetric and isentropic efficiency under wide range of pressure ratio. Improvement of the compressor design can be made to limit increases in temperature, reduce relative velocity and increase the overall efficiency of the machine.

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Internally geared screw machines with ported end plates

Cited by 6 publications

References 3 publications

Influence of rotor geometry on tip leakage and port flow areas in gerotor-type twin screw compressors

Influence of rotor geometry on tip leakage and port flow areas in gerotor-type twin screw compressors

Basic design procedure for an internally geared screw compressor

Design and analysis of conical rotary compressor

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