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
- Full Text: false
- Reviewed:
- 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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- Reviewed:
- 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
Characterization of limacon gas expanders with consideration to the dynamics of apex seals and inlet control valve
- Authors: Phung, Truong , Sultan, Ibrahim
- Date: 2018
- Type: Text , Journal article
- Relation: Journal of Engineering for Gas Turbines and Power Vol. 140, no. 12 (2018), p. 1-11
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- Reviewed:
- Description: Limacon machine, of which the relative motion between the rotor and housing follows the limacon curve, belongs to a class of rotary positive displacement machines. The profiles of rotors and housings of those machines can be constructed of either limacon or circular curves, hence the names: limacon-to-limacon, circolimacon, and limacon-to-circular machines. This paper presents the investigation into the thermodynamic performance of the limacon-to-circular machines with the presence of apex seals and inlet valve. This paper sets out by briefly introducing the limacon technology and the construction of the limacon-to-circular machine working volume. The mathematical descriptions of ports positions and areas have also been introduced. The paper then discusses the flow and phase composition of working fluid through the working chambers as well as how the fluid velocity is modeled and calculated. Then the seal dynamic model and response of inlet valve are presented followed by the machine thermodynamic model. A case study has also been presented to show the responses of seals and inlet valve during the machine operation.
On the apex seal analysis of limaçon positive displacement machines
- Authors: Phung, Truong , Sultan, Ibrahim , Appuhamillage, Gayan
- Date: 2018
- Type: Text , Journal article
- Relation: Mechanism and Machine Theory Vol. 127, no. (2018), p. 126-145
- Full Text: false
- Reviewed:
- Description: Rotary machines, and limaçon machines in particular, offer a better power to weight ratio compared to reciprocating machines; however, leakage due to improper apex and side sealing have prevented rotary machines from thriving. In this paper, a modelling approach is presented to analyse the vibration of apex seal during the machine operation and the power loss caused by the seal friction. The seal and spring are modelled as a spring-mass system in which the seal deformation is negligible. The seal-groove relative positions have then been categorised into nine different possible cases based on the number of contact points between the seal and the seal groove. A case study has been presented to demonstrate the reliability of the model.
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.
- Full Text:
- Reviewed:
- 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