離心泵葉輪內流場研究

The Study of Impeller Internal Flow Field in Centrifugal Pumps

吳三賢(San-Hsien Wu)

指導教授 ： 蘇艾

元智大學/工程學院/機械工程學系/碩士(1995年)

摘要

中文提要: 離心泵通常均設計於最高效率點運轉，但在許多場合則須要
有大的流量變化操作範圍且需 長時間運轉於此範圍。於低流量時泵之葉
輪由於會產生前迴漩，迴流與分離而會有噪音、 振動；旋渦真空及徑向
推力過大情形發生。因此在預測非操作點之性能時，工業界常以實 驗結
果得來之半經驗公式來應付。但欲設計氣動力學性能良好之葉片進而確實
掌握操作點 及非操作點之狀況則必須對葉輪通道內複雜之3-D內流場有
較深一層的認識。此為當今在 設計渦輪機，由其是對離心式泵及壓縮機
之新趨勢。實際上工程師對設計葉片的外型具有 優良的空氣動力學性能
且能滿足結構強度要求是非常有挑戰性的工作。當然其中有許多困 難待
克服。設計方法一般均為間接法，即設計者選擇一符合整體大小及限制之
葉片形狀( 如進出口流角、葉片最大厚度及區域、翼形前緣及後緣之小
圓半徑) 來計算其流場效應； 包含流體特性、速度和方向。這些計算出
的物理量均必須在流線上或排在元件中之網格點 上。
英文提要: In general, centrifugal pumps are designed to operate
near their highest effic iency range. However, the pumps need
to operate at varying flow rates in many occasions. As we know,
the pre-rotation, recirculation and separation phenomen a are
encountered at blade passage at low flow rates. In addition,
noise, vibr ation, cavitation and high radial thrust are
accompanied under these operation conditions. Therefore, the
semi-empirical formulations are used to predict the off-design
conditions in industry. The actual trend in modern design
technique s for turbomachines, particularly for centrifugal
pumps and compressors; goes towards a deeper understanding and
a better prediction of the complex 3-D inte rnal flow. This
accomplishment is not only necessary for an aerodynamic design
of blades but also provides a better way to predict off-design
conditions. In practice, engineers are often interested in
designing a profile that has exce llent aerodynamic performance
and satisfies the requirements on structure and strength. Of
course, there are a lot of difficulties. The design methods are
most commonly indirect, in which the designer chooses a geometry
compatible with the overall dimensions and constraints(e.g.,
the flow angle at inlet and exit, the maximum thickness of
profile, the position of maximun thickness, and the radii of
small circles at leading and trailing edge) already decided and
proceeds to calculate the flow properties, velocities and
directions either on computed streamlines or on a grid of
points through the machines.

關鍵字

離心泵 ； 葉輪 ； 流場

並列摘要

無資料

並列關鍵字

Centrifugal Pumps ； Impeller ； Flow Field