發(fā)布時間：2018-04-10 11:02

  本文選題：離心泵 + 固液兩相　；參考：《浙江大學》2013年博士論文

【摘要】：離心泵通常主要在穩(wěn)定工況下運行,其工作轉速、工況等基本不變或者變化非常緩慢,因此對離心泵的研究主要集中在穩(wěn)定工況下進行。隨著離心泵應用領域的拓展以及系統復雜程度的提高,離心泵也會在非穩(wěn)定工況下運行,如啟動、停機和轉速變化等瞬態(tài)工況,離心泵在非穩(wěn)定工況運行的水力性能日益受到重視,因此非常有必要開展離心泵在瞬態(tài)工況下的性能研究。 本論文以在瞬態(tài)工況下運行的離心泵為研究對象,重點對啟動過程中的水力性能進行了較為詳細和深入的系統研究,獲得了當輸送介質中含有固體顆粒時的離心泵瞬態(tài)啟動特性。論文首先根據動量矩定理提出了一種描述不可壓縮流體機械瞬態(tài)操作條件下性能的廣義歐拉方程式,借助于該方程式開展離心泵在各類瞬態(tài)操作條件下附加理論揚程的定量計算；其次,運用動網格方法進行了離心泵啟動過程的數值仿真計算研究,建立了基于數值模擬的離心泵瞬態(tài)性能研究方法；再次,開展了離心泵啟動過程的外特性實驗測試研究,借助于無量綱分析方法揭示了離心泵啟動過程的瞬態(tài)特性；最后,采用數值模擬方法開展了離心泵輸送介質中含固體顆粒時的啟動過程流動計算,獲得了其瞬態(tài)特性。 論文的主要研究工作如下： 1.從動量矩定理和水力機械內部流動理論出發(fā),推導了一種描述不可壓縮流體機械瞬態(tài)操作過程性能的廣義歐拉方程式。該方程式可較全面地反映了整個葉片厚度變化和葉片型線變化對附加理論揚程的影響,并可被用于泵、風機、透平等不可壓縮流體機械在各類瞬態(tài)操作過程中的附加理論揚程(或壓頭、壓升)的定量預測。 2.運用動網格方法開展了離心泵輸送清水介質時的快速啟動過程的數值模擬研究,建立了基于數值模擬的離心泵瞬態(tài)操作過程的研究方法。論文研究工作中,建立了一個包含離心泵模型在內的循環(huán)管路系統,并在系統中設置了定壓點,數值模擬中對整個系統進行計算。通過數值計算獲得了啟動過程中的許多特性,包括外特性的變化和內部流場的演化特性。進口壓力呈現先降后升特性,流量在啟動初期上升較為緩慢。無量綱流量在初始階段快速上升至穩(wěn)定值；無量綱揚程在啟動初始階段存在極大值,隨后迅速下降低于準穩(wěn)態(tài)值,而后又不斷上升接近于準穩(wěn)態(tài)值。 3.在所搭建的離心泵瞬態(tài)性能測試實驗臺上,對三種典型葉輪結構(普通閉式葉輪、復合葉輪和開式葉輪)的離心泵進行了清水介質的啟動過程實驗測試研究。通過實驗獲得了啟動過程中轉速、流量、揚程和軸功率隨時間的變化結果,分析了各個物理量的變化特性。啟動過程中轉速上升規(guī)律基本穩(wěn)定,不依賴于啟動后穩(wěn)定工況點的變化而變化；流量在啟動初期上升較為緩慢,延遲于轉速而上升到穩(wěn)定值,并且隨閥門開度的增加延遲變得更為嚴重；在啟動過程中普遍存在壓力沖擊和軸功率沖擊現象。 4.首先采用基于歐拉-歐拉方法的多相流模型,對固液兩相流中固相屬性對水力輸送性能的影響以及泵流道內固體顆粒的分布進行了數值計算研究,分析了內部流場的變化特性。在離心泵啟動實驗中獲得的轉速與流量測試結果基礎上,編寫用戶自定義函數施加到泵葉輪上和進口處充當計算邊界條件,采用動網格方法開展了離心泵輸送介質中含固體顆粒時的啟動計算。研究發(fā)現當輸送介質發(fā)生變化時,啟動過程所表現出的性能差別是非常大的。啟動前期瞬態(tài)性能基本相同,差別主要集中在啟動后期；輸送固液兩相流時的揚程呈現先升后降的變化特性,明顯區(qū)別于介質為清水時的持續(xù)上升趨勢；當輸送介質含固體顆粒時,揚程滯后于清水介質時的情形而達到穩(wěn)定狀態(tài)。
[Abstract]:Centrifugal pumps usually run in stable condition, the working speed, working basic constant or change very slowly, so the research of centrifugal pump is mainly concentrated in the stable condition. With the application development of the centrifugal pump and the increase of system complexity, centrifugal pump will run in unsteady conditions such as start, stop and speed change of transient conditions, the centrifugal pump becomes more and more important in the hydraulic performance of non steady operation, so it is very necessary to carry out research on the performance of centrifugal pump under transient conditions.
In this paper, a centrifugal pump running in transient conditions as the research object, focusing on the hydraulic performance in the process of starting a more detailed and in-depth study of the system, the centrifugal pump transient when the transport medium containing solid particles when the starting characteristics. Firstly, according to the momentum moment theorem is proposed to describe not the generalized Euler equation of compressible fluid mechanical properties of transient operating conditions, with the help of this equation to carry out quantitative pump additional theoretical head in all kinds of transient operating condition are calculated; secondly, using the dynamic mesh method obtained from numerical simulation of heart pump start calculation in the course of study, a numerical simulation method based on the study on the transient performance of centrifugal pump again, the external characteristics; experimental study of centrifugal pump during starting period, with the help of dimensionless analysis method to reveal the transient of the centrifugal pump during starting period In the end, the numerical simulation method is used to carry out the calculation of the starting process flow of the solid particles in the conveying medium of the centrifugal pump, and the transient characteristics are obtained.
The main research work of this paper is as follows:
Starting from the 1. theorem of moment of momentum and hydraulic mechanical flow theory, generalized Euler equation is derived to describe an incompressible fluid mechanical transient operation process performance. This equation can reflect the influence of the blade thickness and the blade profile changes on the theory of additional lift, and can be used to pump air. Additional theoretical lift machine, such as turbine incompressible fluid in various types of machinery during transient operation (or pressure, pressure rise) quantitative prediction.
2. simulation study using dynamic mesh method to carry out a centrifugal pump water medium fast startup process is developed based on the numerical method of centrifugal pump transient process based on numerical simulation. The research work, establish a complete model of centrifugal pump, circulation system, and set up a constant pressure point in the system in the calculation of the whole system. The numerical simulation obtained by numerical calculation. Many characteristics in the starting process, including the evolution characteristics of external characteristics and internal flow field changes. The inlet pressure is decreased and then the flow characteristics in the early start to rise more slowly. The dimensionless flow in the initial stage of rapid rise to a stable value; the dimensionless head in the initial stage of starting up the maximum value, then decreased rapidly than the quasi steady value, and then rising close to the quasi steady state value.
3. in the transient performance of centrifugal pump test bench is built on three kinds of typical structure of impeller (ordinary closed impeller, complex impeller and open impeller centrifugal pump) were studied experimental start-up process of water. Through the experiment speed, start the process of the flow, the changes of head and shaft power over time, to investigate the characteristics of various physical quantities. During the startup speed rise of basic stability, does not depend on changes in the starting point and the stable condition after change; flow increases slowly in the early start, delay in speed and rise to a stable value, and with the increase of valve opening delay becomes more serious there; pressure shock and shaft power shock phenomenon during startup.
The first 4. phase flow model based on Euler Euler method, the effect of solid phase properties of solid-liquid two-phase flow on the transmission performance of hydraulic pump flow and distribution of solid particles was studied numerically, analyzed the change characteristics of the internal flow field of centrifugal pump. In the experiment the speed and flow on the basis of the test results and write user defined functions applied to the pump impeller and inlet as boundary condition, the dynamic mesh method containing solid particles in the conveying medium when starting the calculation of centrifugal pump was carried out. The study found that when the transmission medium is changed, the performance difference is shown in the starting process is very large. Before the start of transient performance the same, the difference is mainly concentrated in the late start; transportation of solid-liquid two-phase flow when the head changes characteristics at first and then decreased, significantly different from the medium water holding time The rising trend is continued. When the medium contains solid particles, the lift falls behind the water medium and reaches a stable state.

【學位授予單位】：浙江大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TH311

【參考文獻】

相關期刊論文 前10條

1 練永慶;田兵;王樹宗;吳朝暉;;空氣渦輪泵發(fā)射系統發(fā)射過程仿真分析[J];兵工學報;2011年02期

2 徐一鳴;徐士鳴;;核主泵惰轉轉速計算模型的比較[J];發(fā)電設備;2011年04期

3 王樂勤,吳大轉,胡征宇,鄭水英;基于鍵合圖法的葉片泵啟動特性仿真[J];工程熱物理學報;2004年03期

4 徐朝暉,吳玉林,陳乃祥,劉宇,張梁,吳玉珍;基于滑移網格與RNG湍流模型計算泵內的動靜干擾[J];工程熱物理學報;2005年01期

5 吳大轉;王樂勤;胡征宇;;離心泵快速啟動過程外部特性的試驗研究[J];工程熱物理學報;2006年01期

6 陳頌英;李春峰;曲延鵬;隋榮娟;;離心泵在啟動階段的水力特性研究[J];工程熱物理學報;2006年05期

7 吳大轉;焦磊;王樂勤;;不同啟動加速度下離心泵瞬態(tài)水力性能的試驗研究[J];工程熱物理學報;2008年01期

8 王樂勤;李志峰;戴維平;吳大轉;;離心泵啟動過程內部瞬態(tài)流動的二維數值模擬[J];工程熱物理學報;2008年08期

9 吳大轉;焦磊;王樂勤;;離心泵啟動過程瞬態(tài)空化特性的試驗研究[J];工程熱物理學報;2008年10期

10 吳大轉;許斌杰;李志峰;王樂勤;;離心泵瞬態(tài)操作條件下內部流動的數值模擬[J];工程熱物理學報;2009年05期

相關博士學位論文 前2條

1 黃良勇;低揚程大型泵站過渡過程特性研究[D];江蘇大學;2006年

2 李志峰;離心泵啟動過程瞬態(tài)流動的數值模擬和實驗研究[D];浙江大學;2009年

相關碩士學位論文 前2條

1 武剛;基于虛擬儀器的流體輸送綜合測試系統的研究[D];浙江大學;2005年

2 隋榮娟;離心泵在啟動階段的水力特性及內流機理研究[D];山東大學;2006年

，

本文編號：1730924