螺旋離心泵內(nèi)能量轉換特性及設計方法研究
發(fā)布時間：2018-10-21 16:03
【摘要】：固體物料的水力輸送是固液兩相流典型的工程應用,螺旋離心泵作為一類新型的雜質(zhì)泵,在輸送固液兩相流體時具有突出的優(yōu)越性,如高效、耐磨、抗堵塞等。其獨特的螺旋型葉輪在輸送固液兩相流介質(zhì)時的能量轉化規(guī)律和非穩(wěn)態(tài)流體動力學特性與傳統(tǒng)離心泵葉輪必然有較大不同。螺旋離心泵已有的研究成果主要集中在對設計方法、外特性及內(nèi)部流場結構方面的研究,而對螺旋離心泵內(nèi)能量轉換特性的研究相對比較少,尤其是對泵在輸送固液兩相流時葉輪和壓水室內(nèi),不同區(qū)域能量傳遞、轉化和耗散過程的研究更是缺乏。 本文通過試驗和數(shù)值計算相結合的方法,重點研究了螺旋離心泵內(nèi)沿葉輪螺旋流道及壓水室流向不同區(qū)域,在清水和固液兩相流介質(zhì)時能量轉換的能力與影響因素,揭示了在輸送清水和固液兩相流介質(zhì)時葉輪和螺旋型壓水室內(nèi)穩(wěn)態(tài)和非穩(wěn)態(tài)能量的時空分布規(guī)律及轉換特性。并在此基礎上,提出了基于兩相流速比理論的葉輪型線方程和壓水室水力設計方法。本文主要研究內(nèi)容分為3個部分： 1.螺旋離心泵在輸送清水介質(zhì)時葉輪和壓水室內(nèi)能量轉換特性。 分別從穩(wěn)態(tài)和非穩(wěn)態(tài)兩個方面研究了葉輪輸入功率、能量轉換效率和能量損失的特點,結果表明,葉輪對流體做功主要表現(xiàn)為壓力做功,而流體的粘性力做功只占較小的比重。給出了葉輪螺旋段、過渡段和離心段劃分方法和依據(jù),發(fā)現(xiàn)葉輪螺旋段是葉輪對流體做功和流體獲得能量的關鍵區(qū)域。 葉輪旋轉時,流道內(nèi)瞬時能量轉換和損失一直在發(fā)生變化,且具有周期性規(guī)律。葉片的不對稱及壓水室和葉輪動靜干涉作用,引起葉輪輸入和輸出功率、葉輪表面壓力的周期性變化,也造成壓水室內(nèi)動靜壓能轉換的不穩(wěn)定。流量變化對于葉輪螺旋段能量轉換效率的影響要大于離心段,離心段對葉輪輸出功率的波動特性起決定作用。 葉輪內(nèi)能量損失的主要形式是湍流耗散和壁面摩擦損失,小流量時以湍流耗散損失為主,大流量時以摩擦損失為主；湍流耗散損失的主要區(qū)域在葉輪出口,摩擦損失的主要區(qū)域在葉輪離心段。壓水室內(nèi)的能量損失主要是隔舌處的沖擊損失和湍流耗散損失,其值隨流量增加呈幾何倍數(shù)增長。 2.螺旋離心泵在輸送固液兩相流時泵內(nèi)的非穩(wěn)態(tài)能量轉換特性。 采用歐拉(Eulerian)固液兩相流模型分別對固相濃度和粒徑變化對葉輪相對軸功率、截面湍流強度、效率、湍動能耗散率、動揚程系數(shù)以及壓水室能量轉換特性的影響進行了非穩(wěn)態(tài)數(shù)值分析。結果表明,固相濃度增加時,泵揚程的平均值有所下降,但波動幅度加大。隨粒徑和固相濃度增加,葉輪輸入相對軸功率波動幅度加大,泵效率的下降幅度也明顯增加,但瞬時效率曲線的高效區(qū)范圍變化不大,其位置是由葉輪、壓水室形狀和兩者的相對位置共同決定的,而與輸送介質(zhì)幾何物性參數(shù)的相關性不強。 葉輪效率和葉輪流道截面上湍流強度表現(xiàn)出較強的周期性變化規(guī)律。固相濃度對湍流強度的影響要大于粒徑變化的影響。隨著固相濃度、粒徑增加壓水室各截面湍流動能耗散率均有增加的趨勢,變化最強烈的截面都是靠近隔舌和喉部位置。葉輪螺旋段流道的螺旋推進作用使得顆粒直徑和液體流速變化導致的湍流耗散率的變化被降低,固相體積分數(shù)和顆粒直徑的變化對葉輪湍動能耗散的影響主要集中在離心段流道區(qū)域內(nèi)。 3.螺旋離心泵固液兩相流水力設計方法 根據(jù)螺旋離心泵在輸送固液兩相流時葉輪內(nèi)能量轉換特性及固相分布規(guī)律,利用固液兩相流速比系數(shù),基于軸向流速匹配的原則,得到了葉輪固液兩相流葉片型線方程。同時基于葉輪和壓水室能量轉換相匹配原則給出了壓水室水力設計方法,并對給出的設計方法進行了數(shù)值驗證,改進后的模型在輸送己知固相濃度兩相流介質(zhì)時泵效率較原模型提高了8.5%,證明了本文給出的設計方法達到了預期的效果。
[Abstract]:The hydraulic transportation of solid materials is a typical engineering application of solid-liquid two-phase flow. The spiral centrifugal pump is a kind of new type of impurity pump. It has outstanding advantages in conveying solid-liquid two-phase fluid, such as high-efficiency, wear-resistant, anti-clogging and so on. The energy conversion rule and non-steady-state fluid dynamics characteristic of the unique spiral impeller in conveying solid-liquid two-phase flow medium are different from that of the traditional centrifugal pump impeller. The research results of the spiral centrifugal pump mainly focus on the research on the design method, the outer characteristic and the internal flow field structure, and the research on the energy conversion characteristics in the spiral centrifugal pump is relatively few, especially the impeller and the pressure water chamber when the pump is in two-phase flow of the conveying solid liquid, The research on energy transfer, transformation and dissipation in different regions is lacking. Through the combination of experiment and numerical calculation, the paper mainly studies the capacity and influence of the spiral flow channel and the pressure water chamber of the spiral centrifugal pump in different areas, and the energy conversion in the two-phase flow medium of clean water and solid solution. The spatial and temporal distribution of steady state and non-steady state energy in both the impeller and the screw-type pressure water chamber when the two-phase flow medium of clean water and solid solution are conveyed is revealed. The characteristics of impeller type line equation and pressure water chamber based on two-phase flow rate ratio theory are presented. Methods: The main contents of this paper are divided into three parts: Part: 1. Inside the impeller and pressure water chamber when the spiral centrifugal pump delivers clean water medium The characteristics of the input power, energy conversion efficiency and energy loss of the impeller were studied from both steady state and unsteady state. The results show that the main performance of the impeller on the fluid is the pressure work, and the hydrodynamic force of the fluid The method and basis for dividing the spiral section, the transition section and the centrifugal section of the impeller are given, and the spiral section of the impeller is found to be the impeller to do work and fluid to the fluid. Critical area of energy. During rotation of the impeller, instantaneous energy conversion and loss in the flow path have been occurring and the pressure water chamber is also caused by the periodic change of the pressure on the surface of the impeller. The influence of flow variation on the energy conversion efficiency of the spiral section of the impeller is greater than that of the centrifugal section, and the centrifugal section is used for the output of the impeller. The main form of energy loss in the impeller is turbulence dissipation and wall friction loss, while small flow is mainly caused by turbulence dissipation loss, while large flow is mainly caused by friction loss; the main area of the turbulent dissipation loss is at the outlet of the impeller. the main area of the wiping loss is in the centrifugal section of the impeller, the energy loss in the pressure water chamber is mainly the impact loss and the turbulent dissipation loss at the baffle, The value of the spiral centrifugal pump increases with the increase of the flow rate. The non-steady-state energy conversion characteristics of two-phase flow of liquid are studied. The relative axial power, turbulent intensity, efficiency, kinetic energy dissipation rate, dynamic lift coefficient and pressure water of the impeller are calculated by Eulerian solid-liquid two-phase flow model, respectively. Non-steady-state numerical analysis was carried out on the effect of the energy conversion characteristics of the chamber. The results showed that the solid phase concentration increased. The average value of pump head decreases, but the fluctuation amplitude increases. With the increase of particle size and solid phase concentration, the amplitude of relative axial power fluctuation of impeller is increased, and the decrease amplitude of pump efficiency is increased obviously, but the range of high efficiency area of instantaneous efficiency curve is not large, and its position is composed of leaves. The shape of the wheel, the pressure chamber and the relative position of the two are determined together and the relationship between the geometric physical properties of the conveying medium is not strong, The turbulence intensity on the cross section shows a strong periodic rule. The effect of solid phase concentration on turbulence intensity is larger than that of particle size variation. With the solid phase concentration, the dissipation rate of turbulent kinetic energy in each section of the pressure water chamber increases with the increase of the solid phase concentration. The change of the turbulent dissipation rate caused by the change of particle diameter and liquid flow velocity is reduced, the volume fraction of solid phase and the change of particle diameter are changed. The influence of the kinetic energy dissipation of the impeller is mainly concentrated in the centrifugal section The hydraulic design method of solid-liquid two-phase flow of spiral centrifugal pump in flow channel region is based on the energy conversion characteristic and solid state of spiral centrifugal pump in the two-phase flow of conveying solid liquid. phase distribution law, using two-phase flow rate ratio coefficient of solid solution Based on the principle of matching the axial flow velocity, the two-phase flow blade type line equation of the impeller solid solution is obtained. At the same time, the hydraulic design method of the pressure water chamber is given based on the matching principle of the energy conversion of the impeller and the pressure water chamber, and the design method is validated and the improved model is improved. The pump efficiency is higher when the two-phase flow medium with known solid phase concentration is conveyed
【學位授予單位】：蘭州理工大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TH311
本文編號：2285623
[Abstract]:The hydraulic transportation of solid materials is a typical engineering application of solid-liquid two-phase flow. The spiral centrifugal pump is a kind of new type of impurity pump. It has outstanding advantages in conveying solid-liquid two-phase fluid, such as high-efficiency, wear-resistant, anti-clogging and so on. The energy conversion rule and non-steady-state fluid dynamics characteristic of the unique spiral impeller in conveying solid-liquid two-phase flow medium are different from that of the traditional centrifugal pump impeller. The research results of the spiral centrifugal pump mainly focus on the research on the design method, the outer characteristic and the internal flow field structure, and the research on the energy conversion characteristics in the spiral centrifugal pump is relatively few, especially the impeller and the pressure water chamber when the pump is in two-phase flow of the conveying solid liquid, The research on energy transfer, transformation and dissipation in different regions is lacking. Through the combination of experiment and numerical calculation, the paper mainly studies the capacity and influence of the spiral flow channel and the pressure water chamber of the spiral centrifugal pump in different areas, and the energy conversion in the two-phase flow medium of clean water and solid solution. The spatial and temporal distribution of steady state and non-steady state energy in both the impeller and the screw-type pressure water chamber when the two-phase flow medium of clean water and solid solution are conveyed is revealed. The characteristics of impeller type line equation and pressure water chamber based on two-phase flow rate ratio theory are presented. Methods: The main contents of this paper are divided into three parts: Part: 1. Inside the impeller and pressure water chamber when the spiral centrifugal pump delivers clean water medium The characteristics of the input power, energy conversion efficiency and energy loss of the impeller were studied from both steady state and unsteady state. The results show that the main performance of the impeller on the fluid is the pressure work, and the hydrodynamic force of the fluid The method and basis for dividing the spiral section, the transition section and the centrifugal section of the impeller are given, and the spiral section of the impeller is found to be the impeller to do work and fluid to the fluid. Critical area of energy. During rotation of the impeller, instantaneous energy conversion and loss in the flow path have been occurring and the pressure water chamber is also caused by the periodic change of the pressure on the surface of the impeller. The influence of flow variation on the energy conversion efficiency of the spiral section of the impeller is greater than that of the centrifugal section, and the centrifugal section is used for the output of the impeller. The main form of energy loss in the impeller is turbulence dissipation and wall friction loss, while small flow is mainly caused by turbulence dissipation loss, while large flow is mainly caused by friction loss; the main area of the turbulent dissipation loss is at the outlet of the impeller. the main area of the wiping loss is in the centrifugal section of the impeller, the energy loss in the pressure water chamber is mainly the impact loss and the turbulent dissipation loss at the baffle, The value of the spiral centrifugal pump increases with the increase of the flow rate. The non-steady-state energy conversion characteristics of two-phase flow of liquid are studied. The relative axial power, turbulent intensity, efficiency, kinetic energy dissipation rate, dynamic lift coefficient and pressure water of the impeller are calculated by Eulerian solid-liquid two-phase flow model, respectively. Non-steady-state numerical analysis was carried out on the effect of the energy conversion characteristics of the chamber. The results showed that the solid phase concentration increased. The average value of pump head decreases, but the fluctuation amplitude increases. With the increase of particle size and solid phase concentration, the amplitude of relative axial power fluctuation of impeller is increased, and the decrease amplitude of pump efficiency is increased obviously, but the range of high efficiency area of instantaneous efficiency curve is not large, and its position is composed of leaves. The shape of the wheel, the pressure chamber and the relative position of the two are determined together and the relationship between the geometric physical properties of the conveying medium is not strong, The turbulence intensity on the cross section shows a strong periodic rule. The effect of solid phase concentration on turbulence intensity is larger than that of particle size variation. With the solid phase concentration, the dissipation rate of turbulent kinetic energy in each section of the pressure water chamber increases with the increase of the solid phase concentration. The change of the turbulent dissipation rate caused by the change of particle diameter and liquid flow velocity is reduced, the volume fraction of solid phase and the change of particle diameter are changed. The influence of the kinetic energy dissipation of the impeller is mainly concentrated in the centrifugal section The hydraulic design method of solid-liquid two-phase flow of spiral centrifugal pump in flow channel region is based on the energy conversion characteristic and solid state of spiral centrifugal pump in the two-phase flow of conveying solid liquid. phase distribution law, using two-phase flow rate ratio coefficient of solid solution Based on the principle of matching the axial flow velocity, the two-phase flow blade type line equation of the impeller solid solution is obtained. At the same time, the hydraulic design method of the pressure water chamber is given based on the matching principle of the energy conversion of the impeller and the pressure water chamber, and the design method is validated and the improved model is improved. The pump efficiency is higher when the two-phase flow medium with known solid phase concentration is conveyed
【學位授予單位】：蘭州理工大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TH311
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