Computations of the Propeller Forces of the High Speed Boats in Waves

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簡歷

基本資料

Project title

Code/計畫編號

MOST103-2622-E019-004-CC3

Translated Name/計畫中文名

高速艇於波浪中螺槳受力之計算

Project Coordinator/計畫主持人

Ching-Yeh Hsin

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Systems Engineering and Naval Architecture

Website

https://www.grb.gov.tw/search/planDetail?id=8312155

Year

2014

Start date/計畫起

01-06-2014

Expected Completion/計畫迄

01-05-2015

Bugetid/研究經費

520千元

ResearchField/研究領域

機械工程

高速艇螺槳性能的評估，除了螺槳於均勻入流中的性能以外，另外會影響其性能的因素有二，一是由於高速所導致的空化，一是高速艇於行進間，由於滑航姿態的改變，將會影響到螺槳入流的改變。本計畫將探討這兩個因素，一是空化，一是高速艇航行中由於波浪所引起螺槳吃水深度對於螺槳受力的影響。本計畫應用黏性流RANS方法與考慮螺槳空化的體積力方法計算螺槳空化，計算結果除進行相互的比較外，並與實驗以及勢流邊界元素法的結果進行比較。在應用真實幾何模擬螺槳單獨試驗的計算模擬上，勢流與黏性流方法的預測皆有一定的精準度。在空化試驗的計算模擬上，勢流方法由於空化模型的限制，僅能夠預測由導緣處產生的片狀空化，無法預測轂部空化及壓力面之空化。而黏性流可正確模擬出轂部空化及片狀空化，且不同氣體體積分率的設定對於整體的空泡範圍影響不大，僅影響葉尖周圍的預測。然而，計算結果顯示黏性流計算對於空化造成的推力損失預測仍需有更高之精準度。體積力方法可以較有效率的模擬計算船體與螺槳的交互作用，本文因此發展一可以考量螺槳空化的體積力方法，對於自由液面以及不同沒水深度的空化效應進行探討。文中藉由計算所得之受力以及流場分析了沒水深度對於空化發生的影響，以及自由液面效應對於空化以及推力下降的影響。文所建立的計算程序由於考量空化，應可加強螺槳在波浪中性能預測的精準度。我們並將應用黏性流RANS方法進行高速艇運動計算，並試圖找出最適當的計算途徑。未來可以船舶運動所得之結果為入流，應用體積力方法進行螺槳於波浪影響下的性能計算。 The propeller performance of a high speed boat will be affected by the planning of the boats due the change of inflow. In this project, the propeller forces affected by the high speed boat in waves will be investigated, and computations will be emphasized on the propeller cavitation evaluations. In this report, the propeller cavitation is computed by the viscous flow RANS method and the body force method considering the propeller cavitation. The computational results are compared to each other, and to the experimental data and results from a potential flow boundary element method. Both viscous flow method and potential flow method provide accurate predictions for propeller open water test simulations. When considering the cavitation, due to the cavitation model, the potential flow boundary element method can only predict sheet cavitation starting from the leading edge, and cannot predict root cavitation or face cavitation. On the other hand, the viscous flow method can correctly predict the root and face cavitations, and the vapor volume fraction did not affect the results much except near the blade tip. Body force method can efficiently simulate the propeller/hull interactions, and we therefore developed a body force method considering the propeller cavitation to investigate the effects of free surface and immersion depth to cavitations. In the report, we have investigated the effects of immersion depth to the cavitation by forces and flow field computed. We have also evaluated the cavitation and thrust decrease due to the influence of free surface. The viscous flow RANS method was also used to compute the high speed boat motions. In the future, the flow field computed from the ship motions can be used as the inflows of the propeller, and the body force method can be applied to the propeller force computations.

Keyword(s)

高速艇
螺槳
波浪效應
船舶運動
邊界元素法
RANS
high speed boat
propeller
wave effect
ship motion
boundary element method
RANS

DSpace CRIS

Computations of the Propeller Forces of the High Speed Boats in Waves

基本資料

Description