scholarly journals The Influence of Rotor Geometry on Power Transfer Between Rotors in Gerotor-Type Screw Compressors

2019 ◽  
Vol 142 (7) ◽  
Author(s):  
Matthew G. Read ◽  
Nikola Stosic ◽  
Ian K. Smith
Keyword(s):  
Performance Indicators ◽  
Input Power ◽  
Power Transfer ◽  
Multi Objective Optimization ◽  
Positive Displacement ◽  
Rotor Profile ◽  
Outer Rotor ◽  
Twin Screw ◽  
Wrap Angle ◽  
Swept Volume

Abstract The configuration of a twin-screw positive displacement machine is proposed, consisting of an internally geared outer rotor meshing with an externally geared inner rotor. Helical rotors with constant profile and pitch are used with parallel rotor axes and stationary end plates incorporating inlet and discharge ports to achieve internal compression or expansion. The focus of this paper is to understand the effect of rotor geometry on two key performance indicators; the swept volume of the machine and the proportion of input power transferred between the inner and outer rotors. This requires a detailed analysis of the limitations on rotor profile generation, the formation of working chambers, and the forces exerted on the rotors. The choice of the rotor for power transfer to or from the machine is shown to be an important consideration, and helical rotors are found to enable lower power transfer between rotors during operation when compared with straight-cut rotors, but with reduced swept volume for the same machine size. For particular applications, this compromise is characterized through multi-objective optimization of the rotor profile and wrap angle in order to identify appropriate configurations for the proposed machine.

Integral Modeling of a Twin-Screw Compressor

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Sarah Van Erdeweghe ◽  
Joris De Schutter ◽  
Eric Van den Bulck
Keyword(s):  
Working Conditions ◽  
Control Volume ◽  
Optimization Procedure ◽  
Future Research ◽  
Screw Compressor ◽  
Positive Displacement ◽  
Rotor Profile ◽  
Twin Screw ◽  
Large Application ◽  
Similarity Law

In this paper, an integral methodology for the modeling of a twin-screw compressor is presented. Starting from a known rotor profile, all the algorithms to calculate the second rotor profile, the size of the control volume, and the compressor's performance are presented. The proposed modeling approach can be applied in an optimization procedure to find the optimal rotor profiles for a given application, with corresponding working conditions. Furthermore, based on the modeling results and substantiated with measurements on different compressor types, a similarity law for positive displacement compressors seems to exist. The existence of a similarity law has large application potential as it could be used to predict the performance of a positive displacement compressor in other than the (lab) tested working conditions. Further investigation of the similarity law for positive displacement compressors is therefore proposed as a key topic for future research.

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

2020 ◽  
pp. 095440892096241
Author(s):  
MG Read ◽  
IK Smith ◽  
N Stosic
Keyword(s):  
Geometric Analysis ◽  
Contact Forces ◽  
Screw Compressor ◽  
Continuous Contact ◽  
Tip Leakage ◽  
Positive Displacement ◽  
Compression Cycle ◽  
Twin Screw ◽  
Wrap Angle ◽  
Port Areas

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.

Development and Optimization of Screw Machines With a Simulation Model—Part I: Profile Generation

1997 ◽  
Vol 119 (3) ◽  
pp. 659-663 ◽  
Author(s):  
N. Stosˇic´ ◽  
K. Hanjalic´
Keyword(s):  
Conjugacy Condition ◽  
Positive Displacement ◽  
Rotor Profile ◽  
Twin Screw ◽  
Compression And Expansion ◽  
Screw Rotor ◽  
Differential Algorithm ◽  
Rotor Profiles ◽  
Generation Procedure ◽  
Thermodynamic Processes

This paper presents a method for the design of twin screw compressors and expanders, which is based on a differential algorithm for defining the rotor profiles and an analytical model of the fluid flow and thermodynamic processes within the machine. Part I of the paper describes the algorithm for screw rotor profile generation. It demonstrates the conjugacy condition which, when solved explicitly, enables a variety of primary arcs to be defined either analytically or by discrete point curves. Its use greatly simplifies the design since only primary arcs need to be specified and these can be located on either the main or gate rotor or even on any other rotor including a rack, which is a rotor of infinite radius. Secondary arcs are then generated automatically from this. By such means any profile combination may be considered. The most efficient were obtained from a combined rotor-rack generation procedure. An example of this combination is given which produces a rotor profile with stiff lobes and a higher throughput than any other known type. Part II describes a mathematical model of the compression and expansion processes within positive displacement machines which has been well proven in its use for the design of reciprocating and screw compressors and screw expanders.

scholarly journals Wireless power transfer system rigid to tissue characteristics using metamaterial inspired geometry for biomedical implant applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramesh K. Pokharel ◽  
Adel Barakat ◽  
Shimaa Alshhawy ◽  
Kuniaki Yoshitomi ◽  
Costas Sarris
Keyword(s):  
Electromagnetic Waves ◽  
Wireless Power Transfer ◽  
Split Ring Resonator ◽  
Input Power ◽  
Power Transfer ◽  
Wireless Power ◽  
Biomedical Implant ◽  
Safety Regulations ◽  
Wireless Power Transfer System ◽  
Tissue Characteristics

AbstractConventional resonant inductive coupling wireless power transfer (WPT) systems encounter performance degradation while energizing biomedical implants. This degradation results from the dielectric and conductive characteristics of the tissue, which cause increased radiation and conduction losses, respectively. Moreover, the proximity of a resonator to the high permittivity tissue causes a change in its operating frequency if misalignment occurs. In this report, we propose a metamaterial inspired geometry with near-zero permeability property to overcome these mentioned problems. This metamaterial inspired geometry is stacked split ring resonator metamaterial fed by a driving inductive loop and acts as a WPT transmitter for an in-tissue implanted WPT receiver. The presented demonstrations have confirmed that the proposed metamaterial inspired WPT system outperforms the conventional one. Also, the resonance frequency of the proposed metamaterial inspired TX is negligibly affected by the tissue characteristics, which is of great interest from the design and operation prospects. Furthermore, the proposed WPT system can be used with more than twice the input power of the conventional one while complying with the safety regulations of electromagnetic waves exposure.

scholarly journals A Converter with Automatic Stage Transition Control for Inductive Power Transfer

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5268
Author(s):  
Lin Chen ◽  
Jianfeng Hong ◽  
Zaifa Lin ◽  
Daqing Luo ◽  
Mingjie Guan ◽  
...  
Keyword(s):  
Input Power ◽  
Effective Control ◽  
Transfer System ◽  
Injection Time ◽  
Power Transfer ◽  
Soft Switch ◽  
Inductive Power Transfer ◽  
Transition Control ◽  
Stage Transition ◽  
Inductive Power

An automatic stage transition converter for an inductive power transfer system is presented in this paper. An effective control strategy with two working stages of independent energy injection stage and free resonance stage is employed in the proposed converter. With the automatic stage transition strategy, when the frequency of the resonance network changes, the ending time of the free resonance stage is automatically determined. At the same time, the phase angle of the free resonance stage is automatically set as half a resonant cycle. As the stage transition is not triggered by the switches, the switch motion can be executed in advance of the transition moments. Time margins are offered for every switch in the converter, which make the switching moments of the switches flexible and the control simple. Another feature of this converter is that during the energy injection stage, the energy is injected into the inductor independently. Therefore, the input power can be easily regulated by adjusting the energy injection time. A prototype for the converter and the inductive power transfer system was implemented experimentally. From the experimental results, the automatic stage transition and power regulation capability of the proposed converter are verified. The switches all operated at the soft switch condition. When the energy injection time was adjusted from 10 μs to 25 μs, the output power changed from 143 W to 740 W.

A multi-objective optimization model for sustainable supply chain network with using genetic algorithm

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Reza Ehtesham Rasi ◽  
Mehdi Sohanian
Keyword(s):  
Supply Chain ◽  
Performance Indicators ◽  
Supplier Selection ◽  
Supply Chain Network ◽  
Sustainable Supply Chain ◽  
Multi Objective Optimization ◽  
Content Type ◽  
Sustainability Performance ◽  
Multi Objective ◽  
Sustainable Supplier Selection

Purpose The purpose of this paper is to design and optimize economic and environmental dimensions in a sustainable supply chain (SSC) network. This paper developed a mixed-integer linear programing (MILP) model to incorporate economical and environmental data for multi-objective optimization of the SSC network. Design/methodology/approach The overall objective of the present study is to use high-quality raw materials, at the same time the lowest amount of pollution emission and the highest profitability is achieved. The model in the problem is solved using two algorithms, namely, multi-objective genetic and multi-objective particle swarm. In this research, to integrate sustainable supplier selection and optimization of sustainability performance indicators in supply chain network design considering minimization of cost and time and maximization of sustainability indexes of the system. Findings The differences found between the genetic algorithms (GAs) and the MILP approaches can be explained by handling the constraints and their various logics. The solutions are contrasted with the original crisp model based on either MILP or GA, offering more robustness to the proposed approach. Practical implications The model is applied to Mega Motor company to optimize the sustainability performance of the supply chain i.e. economic (cost), social (time) and environmental (pollution of raw material). The research method has two approaches, namely, applied and mathematical modeling. Originality/value There is limited research designing and optimizing the SSC network. This study is among the first to integrate sustainable supplier selection and optimization of sustainability performance indicators in supply chain network design considering minimization of cost and time and maximization of sustainability indexes of the system.

scholarly journals MULTI-OBJECTIVE OPTIMIZATION OF WIRELESS POWER TRANSFER SYSTEMS WITH MAGNETICALLY COUPLED RESONATORS AND NONLINEAR LOADS

2019 ◽  
Vol 83 ◽  
pp. 25-42 ◽  
Author(s):  
Johan Winges ◽  
Thomas Rylander ◽  
Carl Petersson ◽  
Christian Ekman ◽  
Lars-Ake Johansson ◽  
...  
Keyword(s):  
Wireless Power Transfer ◽  
Power Transfer ◽  
Multi Objective Optimization ◽  
Wireless Power ◽  
Coupled Resonators ◽  
Nonlinear Loads ◽  
Multi Objective
Sign in / Sign up

Export Citation Format

Share Document