Inverse geometric design for a class of rotary positive displacement machines
- Authors: Sultan, Ibrahim
- Date: 2008
- Type: Text , Journal article
- Relation: Inverse Problems in Science and Engineering Vol. 16, no. 2 (2008), p. 127-139
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- Description: Inverse design techniques in the area of fluid mechanics are normally conducted for continuous flow turbomachines rather than positive displacement devices. However, the work in this article is concerned with a class of rotary positive displacement device referred to as the limaçon-to-limaçon machine. The rotors and housings of these machines are manufactured of limaçon profiles, and are likely to suffer from interference if the rotors are not carefully profiled. Published literature indicates that solutions proposed to tackle the interference problem in these machines will adversely affect their efficiency figures. This notion motivated the work presented in this article, which first introduces the relevant mathematical models of the limaçon-to-limaçon machine and then uses these models to construct an inverse geometric design problem formulation. The proposed model has been coded in a computer program that utilises a Marquardt-Levenberg technique to converge to the required geometric parameters. Case studies are presented at the end of the article to verify the validity of the proposed inverse design model.
- Description: C1
The limacon of Pascal : mechanical generation and utilization for fluid processing
- Authors: Sultan, Ibrahim
- Date: 2005
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers Part C-Journal of Mechanical Engineering Science Vol. 219, no. 8 (Aug 2005), p. 813-822
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- Description: The limaçon of Pascal is a plane curve that possesses some characteristics which qualify it for fluid processing applications. However, the curve has not yet attracted enough attention, neither from industry nor from the mechanical engineering research community, despite the few attempts that have been conducted over the past century. The work presented here is intended to explore various mechanical linkages that can be employed to produce the limaçon and the aspects of these linkages. Mathematical analysis will show that machines based on the limaçon curve possess sinusoidal volumetric relationships and hence, simplified pressure and torque equations can be obtained in closed forms. The concepts discussed here will be demonstrated by using a compressor as a sample application
- Description: C1
- Description: 2003001087
Optimum design of limaçon gas expanders based on thermodynamic performance
- Authors: Sultan, Ibrahim
- Date: 2012
- Type: Text , Journal article
- Relation: Applied Thermal Engineering Vol. 39, no. 4 (2012), p. 188-197
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- Description: Positive displacement expanders are acquiring popularity due to the current push to harvest energy from low-grade heat resources which have been previously overlooked. The limaçon technology does offer a simple and reliable design with a considerable potential for small-size (≤4 kW) power plants. This paper presents a thermodynamic model for the limaçon design and goes on to utilise this model in an optimisation procedure adopted to calculate the expanders geometric parameters for specific power and operating constraints. The numerical method employed to solve the thermodynamic model is presented for the benefit of the reader. Two design case studies, for expanders with and without an inlet control valve, are offered at the end of the paper to prove the validity of the presented concepts and their suitability for the analysis. © 2012 Elsevier Ltd.
Geometric design of the limaçon-to-circular fluid processing machine
- Authors: Phung, Truong , Sultan, Ibrahim
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Mechanical Design, Transactions of the ASME Vol. 143, no. 10 (2021), p.
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- Description: A limaçon machine is a rotary positive displacement device, in which the housing and rotor are constructed of limaçon of Pascal curves. Previous works have been published to investigate the working of these machines in two applications: gas expanders and compressors. This article presents a theoretical investigation into the potential of modifying the rotor profile of the limaçon machines to simplify the machine's manufacturing process and to reduce production cost. The proposed modification will produce new characteristics for the housing-rotor interaction. An outcome that motivates the need to obtain new mathematical models to investigate the housing-rotor interference and describe the volumetric relationship of the new machine. This article also employs an optimization approach to design the best machine for a given set of operating conditions, i.e., expander, compressor, and pump. The outcome of this study confirms the validity of the proposed modification and its potential to produce a limaçon machine with favorable characteristics. Copyright © 2021 by ASME