离心泵前置导叶的优化设计与实验研究
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摘 要
随着国民经济的发展,工程节能问题越来越受到重视。叶片泵作为一种通用
机械,在我国各个领域都得到了广泛的应用,同时也消耗了大量的能源,因此其
节能意义深远、潜力巨大。针对目前工程中常用的几种离心泵工况调节方式(如
节流调节、变速调节)所存在的各种弊端,已有学者提出前置导叶预旋调节理论,
在此基础上,本文提出一种新的前置导叶设计思路,并从理论分析和实验研究等
方面对离心泵预旋调节的基本规律及调节机理进行了研究。
本文作者设计了符合实际工程运用的前导调节机构。借鉴轴流泵孤立叶片水
力设计方法设计三组单吸离心泵前置导叶,采用诱导轮设计方法完成双吸离心泵
两组不同叶高诱导叶片水力设计。搭建离心泵外特性试验台,通过实验完成以下
工作:
1. 三组不同叶型前置导叶对单吸泵效率、功率、扬程的影响,综合考虑发现
弯叶片型前置导叶调节效果要好于直叶片型、扭叶片型前置导叶;弯叶片型前置
导叶能够改善离心泵在非设计工况的水力性能,与无前置导叶最优工况相比,最
高效率提高 2.34%,功率节省 6.53%,达到为离心泵增效节能的目的。
2. 对前置导叶正负预旋、叶片安装方式两种工况进行对比分析发现:(1)正
预旋能够降低离心泵功率消耗、将离心泵高效区往小流量偏移;负预旋能够提高
离心泵扬程、将离心泵高效区往大流量偏移。(2)前置导叶 A型安装方式要优于
B型安装方式。
3. 带有诱导叶片双吸泵虽然扬程略有降低、在大流量区域效率降低,但是其
功率消耗降低,最大节能 3.34%,而且高效区往小流量偏移。通过对两组不同叶高
诱导叶片对双吸泵外特性的影响,发现 14mm 叶高诱导叶片调节效果要明显好于
20mm 叶高诱导叶片,其能够有效的将双吸泵高效区往小流量偏移,同时降低功率
消耗。
在大量实验结果的基础上,通过从离心泵叶轮进口流动状态、前置导叶导致
的水力损失等方面来分析不同叶型前置导叶调节效果差异的原因,为离心泵前置
导叶预旋调节的研究提供一定的实验参考。
关键词:离心泵 前置导叶 预旋调节
ABSTRACT
Energy conservation has been taken more and more seriously by the country because of
the development of national economy. As being all-purposed mechanism, pump is wise
used in varied area and consumes a lot of energy sources at present. Therefore, the
energy-saving of pump has profound significance and huge potential. In view of the
drawback of several commonly used operating adjustment way for centrifugal pump
(such as variable speed regulation and throttle regulation) in engineering application ,
some scholar has put forward a new operating adjustment way called the adjustable inlet
guide vane regulation for centrifugal pump ,on this basis, a new design idea of
adjustment mechanism of pre-whirl is raised in this paper, and adjustment mechanism of
pre-whirl regulation were researched by the methods of theoretical analysis and
experimental study.
In this paper, the author has designed an adjustment mechanism of inlet guide vane
which suit for the real project usage. Three groups single pump of adjustment
mechanism of inlet guide vane were raised referencing by the insulate vane hydraulic
design concept, completing double-suction centrifugal pump of two different leaf
hydraulic design of high pre-diffuser by Inducer design method. The experiment
equipment was set up which was used for testing the hydraulic performance of the
centrifugal pump, experimental work done by the following:
1. How to affect the efficiency, power and lift of Single-suction pump by three
different leaf type front guide vanes, and found that, as to adjustment efficiency, the
Curved blades front guide vane was better than the straight blade front guide vane and
twist blade front guide vane. The Curved blades front guide vane can improve the
hydraulic performance of the centrifugal pump at off-design operating conditions. When
compared with the performance of the centrifugal pump without guide vane, the peak
efficiency could be increased by 2.34%、power saving of 6.53%. Therefore, the goal of
the efficiency increasing and the energy saving for centrifugal pump were achieved.
2. Comparing and analyzing two working conditions such as positive and negative
adjustment mechanism of pre-whirl regulation 、the installation of blade, and found
that:(1) The positive pre-whirl regulation can reduce the consumption of Centrifugal
pump power, and make the efficient area move to the small flow set. Similarly, the
negative pre-whirl regulation can raise the head of Centrifugal pump, and make the
efficient area move to the large flow set. (2) As to the installation of the inlet guide
vanes, Type A is superior to Type B.
3. The double suction pump with the induced leaf has lower head slightly, and has
lower efficiency in the large flow area ,but with the reduction of its power
consumption ,so it can save energy of 3.34% mostly, and the high efficiency area will
move to small flow as well. Comparing and analyzing two induced leaf with different
heigh, and found that, as to adjustment efficiency, the size 14mm was obviously better
than the size 20mm. It can migrate the high efficient flow of double suction pump to the
small flow area, at the same time reduce the power.
Based on the numerous experimental results, analysis the positive and negative
pre-whirl regulation principles and the reason of differences in adjustable effect of
different blade guide vane by the centrifugal pump fluid flow at the impeller inlet,
hydraulic loss caused by front guide vane, provide some references for the study of
centrifugal pump adjustment mechanism of inlet guide vane .
Key word: fluid flow, inlet guide vane, pre-whirl regulation
目 录
中文摘要
ABSTRACT
第一章 绪 论 ...............................................................................................................1
§1.1 选题背景与意义 ...............................................................................................1
§1.2 离心泵常用工况调节方法 ...............................................................................2
§1.2.1 节流调节 .................................................................................................2
§1.2.2 变速调节 .................................................................................................2
§1.2.3 其他工况调节方法 .................................................................................2
§1.3 前置导叶预旋调节应用 ...................................................................................3
§1.3.1 前置导叶调节技术在风机中的应用 .....................................................3
§1.3.2 前置导叶调节技术在水泵中的应用 .....................................................4
§1.4 本文所研究内容 ...............................................................................................5
第二章 离心泵前置导叶基本理论 ...............................................................................7
§2.1 表征离心泵性能的基本参数与曲线 ................................................................7
§2.1.1 离心泵性能的基本参数 ..........................................................................7
§2.1.2 离心泵水力损失 ......................................................................................8
§2.1.3 离心泵性能曲线 ....................................................................................10
§2.2 前置导叶预旋调节基本原理 ..........................................................................12
第三章 前置导叶对单吸离心泵外特性影响研究 .......................................................16
§3.1 单吸离心泵前置导叶水力设计 ......................................................................16
§3.1.1 单吸离心泵前置导叶叶片设计 ............................................................16
§3.1.2 前置导叶旋转调节机构设计 ................................................................20
§3.1.3 主要实验装置介绍 ................................................................................23
§3.2 直叶片前置导叶对离心泵外特性影响 ..........................................................27
§3.2.1 直叶片前置导叶实验参数 ....................................................................27
§3.2.2 直叶片前置导叶正预旋对离心泵外特性影响 ....................................28
§3.2.3 直叶片前置导叶负预旋对离心泵外特性影响 ....................................30
§3.3 弯叶片前置导叶对离心泵外特性影响 ..........................................................31
§3.3.1 弯叶片前置导叶实验参数 ....................................................................31
§3.3.2 弯叶片前置导叶正预旋对离心泵外特性影响 ....................................32
§3.3.3 弯叶片前置导叶负预旋对离心泵外特性影响 ....................................34
§3.4 扭叶片前置导叶对离心泵外特性影响 ..........................................................36
§3.4.1 扭叶片前置导叶实验参数 ....................................................................36
§3.4.2 扭叶片前置导叶正预旋对离心泵外特性影响 ....................................36
§3.4.3 扭叶片前置导叶负预旋对离心泵外特性影响 ....................................38
§3.5 不同叶型前置导叶对离心泵外特性影响的比较 ..........................................40
§3.5.1 直叶片与弯叶片前置导叶对离心泵外特性影响在工况点对比 ........40
§3.5.2 扭叶片与弯叶片前置导叶对离心泵外特性影响在工况点对比 ........43
§3.6 离心泵前置导叶安装方式比较 ......................................................................46
§3.7 前置导叶引起的水力损失分析 .....................................................................49
§3.7.1 前置导叶水力损失实验装置 ................................................................49
§3.7.2 前置导叶水力损失实验研究 ................................................................49
第四章 带有诱导叶片的双吸离心泵外特性实验研究 .............................................52
§4.1 双吸离心泵诱导叶片的设计 ..........................................................................52
§4.2 双吸离心泵诱导叶片的布置 ..........................................................................54
§4.3 诱导叶片对双吸离心泵外特性影响分析 ......................................................56
第五章 结论与展望 .......................................................................................................58
§5.1 主要工作和结论 ..............................................................................................58
§5.2 对未来工作的展望 ..........................................................................................58
符号表 .............................................................................................................................60
参考文献 .........................................................................................................................61
在研期间公开发表的论文和承担科研项目及取得成果 .............................................64
致谢 .................................................................................................................................65
第一章 绪论
- 1 -
第一章 绪 论
§1.1 选题背景与意义
随着国民经济的发展,工程节能问题越来越受到重视。叶片泵作为一种通用
机械[1],在我国石油化工,农田灌溉,航天航空,城市给排水,水利水电工程和船
舶推进等各个领域都得到了广泛的应用,同时也消耗了大量的能源,更有专家估
计,泵的能耗约占世界总能耗的 20%,在化工行业中高达 26%,而在电力和石油
行业中更是分别高达 50%和55%。离心泵更是由于实用范围广(包括流量、扬程、
及对输送介质的适应性)、体积小、结构简单、操作费用低等诸多优点在工农业等
行业中得到了广泛运用[2]。根据 2004 年调查资料显示[3],全国工业泵产量约为 329
万台,其中离心泵约占泵总量的 50%,在欧洲其他国家离心泵所占比重甚至高达
80%。因此,在能源日趋紧张的现在,离心泵的节能研究对于我国国民经济的发展
将起到十分重要的作用,其意义深远、潜力巨大、经济效益和社会效益都将十分
显著。
在实际工程中,离心泵的运行效率普遍较低、能耗过大。引起离心泵效率偏
低的原因主要来自以下两个方面:(1)传统设计不能满足日益复杂的生产需要[4],
现有的传统叶片泵水力设计方法,通常是根据某一使用工况所给定的性能参数来
进行设计,因此在非设计工况,叶片泵的水力性能通常无法保证;然而在多数叶
片泵的使用现场,通常都要求其能够适应较宽的工况范围,即要求叶片泵在偏离
工况运行。由于工况的变化和流体的粘性作用,此时在泵叶轮流道内将产生叶道
涡、回流和脱落,显然这些复杂的流态将会严重影响叶片泵的水力性能。(2)水
泵运行工况点调节方法不当[5],水泵的经济运行需要建立在合理的泵机组工况调节
和控制的基础上,因此水泵的运行调节问题是水泵节能的关键。泵的运行工况点
由水泵和管网特性共同决定,因此通过改变管网特性或水泵特性都能够达到调节
泵运行工况点的目的。目前在高层建筑居民生活用水系统、中央空调循环水系统
和电站锅炉给水系统等管网中,由于在系统设计时往往对管网负荷压力和阻力难
以准确估算,因此在这些系统中的水泵通常是按照系统所需要的最大流量来进行
选型设计,从而导致离心泵选型过大。为了满足用户的要求,目前通常采用的方
法是通过管道阀门的节流作用来改变管路特性,进而达到调节离心泵运行工况点
的目的[6]。该方式的主要缺点是是容易导致离心泵在偏离最优工况运行,且节流调
节能量损失严重。
研究表明[7],为了提高离心泵实际运行时的水力性能,除了重视泵自身的节能,
摘要:
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摘要随着国民经济的发展,工程节能问题越来越受到重视。叶片泵作为一种通用机械,在我国各个领域都得到了广泛的应用,同时也消耗了大量的能源,因此其节能意义深远、潜力巨大。针对目前工程中常用的几种离心泵工况调节方式(如节流调节、变速调节)所存在的各种弊端,已有学者提出前置导叶预旋调节理论,在此基础上,本文提出一种新的前置导叶设计思路,并从理论分析和实验研究等方面对离心泵预旋调节的基本规律及调节机理进行了研究。本文作者设计了符合实际工程运用的前导调节机构。借鉴轴流泵孤立叶片水力设计方法设计三组单吸离心泵前置导叶,采用诱导轮设计方法完成双吸离心泵两组不同叶高诱导叶片水力设计。搭建离心泵外特性试验台,通过实...
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作者:牛悦
分类:高等教育资料
价格:15积分
属性:68 页
大小:2.23MB
格式:PDF
时间:2024-11-19