碩士 / 國立中興大學 / 機械工程學系所 / 98 / The water pump with claw rotors used in this study was invented by Liung Feng Industrial Co., LTD. This is a positive displacement pump consisting of rotos with conjugated curves. The internal leakage of this pump is studied in this paper. In the whole operating process of water pump with claw rotors, including water absorption, delivery, and compression to water outlet, leakages may occur at any time. By investigating the ways that internal leakage occurs, and the relationship between leakage flow rate and clearance as well as head, leakage flow rate can thus be reduced, thereby further increasing the bulk efficiency of water pump with claw rotors.
Two ways of investigation were carried out. The first one was to establish a two-dimensional steady leakage mode, and then combine this model with a quasi-dimensional dynamic mode to calculate the whole leakage flow rate as claws are rotating. The basic formula of fluid mechanics is used to set up the two-dimensional leakage mode. The internal leakage route and leakage flow rate is analyzed, and the experiment of the characteristics of water pump with claw rotors is carried out, which is then compared with the calculation results of leakage mode to amend the theoretical mode. The quasi-dimensional mode is applied to discuss the pressure change formed by volume change when rotors rotate and the flow rate change caused by pressure change. The results show that the average error of 0.03mm clearance is 48.71%, the average error of 0.06mm clearance is 38.94% and the average error of 0.08mm clearance is 45.1%.
The second method is the numerical solution of two-dimensional model. Fluent, a CFD program was utilized to simulate value and carry out static and dynamic analysis. At static analysis, if rotors are static, the leakage through the contact line between the tip of claw and outer case and the leakage through two contacting claws were simulated, respectively. At dynamic analysis, dynamic mesh was applied to simulate rotors and the flow field between claws and outer casing was applied. These are applied to determine the mass flow rate output while rotors are rotating. The simulation results showed that two-dimensional mode could not estimate effectively the leakage flow rate of water pump with claw rotors.
In this study, the analysis of applying water pump with claw rotors on water jet propulsion of ships is discussed. Moreover, submarine is used as vector to discuss the matching problems between ships and water pump with claw rotors. Submarine is assumed moving forward at constant speed, In case using 4 claw rotor pumps of CP900 as power source. It could produce more than 223,000 N of thrust and the ship speed of up to 13 knot.
| Identifer | oai:union.ndltd.org:TW/098NCHU5311020 |
| Date | January 2010 |
| Creators | Hong-Jin Lin, 林宏縉 |
| Contributors | 盧昭暉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 106 |
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