共查询到20条相似文献,搜索用时 140 毫秒
1.
本文从降低除氧器设置高度和适应除氧器滑压运行出发.提出采用带有诱导轮的变速给水泵,以利降低泵组的必需汽蚀余量,经6个不同设计参量的诱导轮与100D16型多级离心泵的配合试验,测定结果表明:其中最佳的配合可使泵组必需汽蚀余量仅为原泵的1/5.效率较原泵提高6%,适应运行范围扩大了24.6%. 相似文献
2.
文中对某2×300 MW及2×330 MW供热机组锅炉给水泵液力偶合器改变频器调速方案进行了现场调研,计算了变频改造后各种工况下除氧器至给水泵入口段的管路损失,并结合前置泵的运行数据对给水泵入口有效汽蚀余量和必须汽蚀余量进行了校核计算。结果表明:变频改造后,其前置泵转速在1 000~1 490 r/min范围内变化时,给水泵组入口有效汽蚀余量均大于其必需汽蚀余量。该改造方案能够满足给水泵组汽蚀安全性要求。 相似文献
3.
凝结水旁路参与调频是一种增强机组调频能力的有效方法,但调频过程中除氧器暂态特性可能会受到一定的影响,从而影响前置泵的运行安全。本文介绍了凝结水旁路参与调频的原理和方案,提出了此过程中除氧器前置泵暂态安全性计算的必要性。基于三点假设,构建了除氧器中凝结水焓值和工作压力、前置泵入口给水焓值和入口汽化压力、前置泵入口温度和有效汽蚀余量的计算模型。结果表明:40%凝结水旁路开度下前置泵有效汽蚀余量最大会下降13.75 m,对安全性造成威胁。该研究为凝结水旁路参与调频的可行性提供理论基础。 相似文献
4.
5.
给水泵和给水前置泵汽蚀余量计算中各项参数的取值将直接影响除氧器标高的确定,参考国内外工程实践经验.本文对计算中的参数选取提出了推荐意见。 相似文献
6.
汽轮机甩负荷过程中给水泵的汽蚀 总被引:2,自引:0,他引:2
从计算除氧器暂态过程中给水泵入口汽蚀余量的最大降落值入手,分析给水泵在汽轮机甩负荷时汽蚀、断水、失压的原因,并提出了防止措施。 相似文献
7.
介绍了泵的分类和泵类型的选择原则,以及核电汽轮机组汽水分离再热系统(GNS)中,汽水分离再热器(MSR)疏水泵的选型原则、选型设计计算等,还介绍了泵的扬程计算,汽蚀现象和泵的汽蚀余量。 相似文献
8.
针对双吸中开泵吸入室结构的自由性和复杂性加大了设计难度、改变了叶轮的进口流动环量及均匀度并影响泵的汽蚀性能,采用理论方法研究了叶轮进口环量对汽蚀性能的影响,并对一单级双吸中开式离心泵的吸入室进行了优化改型,用数值模拟和试验方法验证了改进型半螺旋吸入室对叶轮汽蚀特性的改善效果。结果表明,进口稍微带正环量能改善叶轮的汽蚀性能,但正环量加大到一定程度后汽蚀又会逐渐恶化;吸入室对叶轮汽蚀的影响因素包括叶轮进口环量和进口流场的均匀度,改进型的半螺旋吸入室提供了叶轮进口的正环量,并提高了叶轮进口流场的均匀度、大幅降低了泵的必需汽蚀余量。 相似文献
9.
《动力工程学报》2013,(5)
采用近场声压法在开式试验台上对IS65-50-160A型离心泵进行了噪声特性试验研究,在变流量和恒流量情形下得到了泵噪声随汽蚀余量的变化规律及频率特性,分析了流量、汽蚀余量及泵入口吸入空气对A声级噪声和不同频率下声压级的影响.结果表明:在变流量情形下,非汽蚀工况下泵的A声级随流量增加而增大,且在高效率区达到最大值;汽蚀初生时,A声级噪声出现显著下降现象;深度汽蚀工况下,A声级噪声显著增加;以1 000Hz和2 000Hz为代表的高频声压级对整体A声级噪声的形成贡献较大;绝大多数流量下的声压级分别在250Hz和1 000Hz时出现峰值,该噪声峰值频率均与叶片通过频率相关.在恒流量下的汽蚀过程中,调节泵入口阀门导致汽蚀发生后,受入口吸入空气影响,泵的A声级噪声显著下降;本研究用泵的汽蚀特征频率为250Hz,该频率汽蚀状态下的声压级峰值比汽蚀前升高了5.9~16.4dB. 相似文献
10.
《中外能源》2018,(12)
化工工艺设计过程中,离心泵性能参数的确定直接影响到泵的设计和选型是否满足装置要求。因此,对泵系统中流量、扬程、汽蚀余量等各项性能参数的计算都必须准确合理。基于泵和管路的特性曲线,同时确定调节阀压降和离心泵扬程的方法有三种:粗算法、根据调节阀流通系数计算和根据调节阀阀组比计算。调节阀阀阻比的方法由于其计算过程考虑到了调节阀的调节性能,使得计算出的调节阀压降和泵的扬程结果更可靠,且算法相对简便,故推荐使用该方法进行泵系统的设计计算。MTO(甲醇制烯烃)装置中再生器催化剂冷却器水循环泵的设计,采用调节阀阀阻比的方法,确定离心泵扬程,进而计算出泵的汽蚀余量、最大关闭压力等各项性能参数,优化了泵的工艺设计过程。同时,为了确保进入催化剂冷却器内的锅炉水流量和压力满足要求,最终保证整个MTO反应再生系统安全稳定运行,水循环泵设为两开一备,并配置不间断电源,要求具备自启动功能。 相似文献
11.
凝结水泵的最佳调节方案分析 总被引:7,自引:0,他引:7
为研究变频调速技术在200MW凝汽机组凝结水泵调节中应用的节能效果,分别按照由机组承担的负荷、除氧器运行方式及调节形式形成的6个方案进行计算分析。首先,由管路性能曲线和泵特性曲线取得各工况点的流量、扬程和效率,椐此并利用电动机和变频器的效率等获得凝结水泵消耗的电功率和全年运行时间段的耗电量,最后可有进行方案比较分析的年费用值。在各方案中采用变频调速方式相对于节流调节方式耗电量要小;调峰负荷下的各种方案要比对应基本负荷的情况耗电量和年费用小;调峰负荷时除氧器滑压运行方式下的变频调速方案是最经济方案。结果表明,虽然凝结水泵的变速调节方式初投资较高,但在各运行工况特别是启停和非设计工况节能潜力巨大,可延长设备寿命,有较强的经济效益,推广应用性强。图4表1参6 相似文献
12.
One of the most undesirable phenomena encountered in the operation of a centrifugal pump is cavitation. It causes structural damage, vibration, and blockage of mass flow, leading to a drop in performance and life of the pump. This study addresses cavitation modeling of a single‐stage centrifugal pump and aims at minimizing cavitation by introducing an inducer upstream of the impeller. Furthermore, it aims at understanding different multiphase modeling schemes by a computational fluid dynamics software and its variation from single‐phase flows. The results from the numerical model are first validated against standard experimental data to check the credibility of the model. After validation, a single‐phase analysis is performed for a wide range of operating conditions. Subsequently, the Schnerr‐Sauer cavitation model is invoked and a multiphase analysis is carried out for the same. The results obtained shows that the inducer is effective in reducing the amount of cavitation for a substantial number of operating conditions. The effectiveness of the inducer is calculated, and a 96% effectiveness is observed at the best efficiency point. Furthermore, data from single‐phase and multiphase analysis are compared, and a method based on absolute pressure is proposed, which can provide results with significant accuracy without the need for expensive computation. Finally, Zwart‐Gerber‐Belamri model is used for cavitation modeling, and the behavior of the scheme is compared with Schnerr‐Sauer model. The pump parameters are compared, and the obtained results show close similarity between the two models. 相似文献
13.
14.
Toshiaki Kanemoto ;Makoto Shimojyo ;Ryunosuke Kawashima ;Daisuke Tanaka ;Akira Inagaki ;Shin Oba 《热科学学报(英文版)》2008,17(1):28-34
To suppress the cavitation in the impellers and to make the turbo-pump lives longer, the inducer was separated from the main impeller and both impellers were driven independently. The performance of the pump and the flow conditions around the impellers were investigated experimentally and the following results were obtained. (1)The main impeller contributes to the flow interaction between the inducer and the main impeller. (2)The rotational speeds of both impellers can be controlled independently in order to suppress simultaneously the cavitation not only in the main impeller, but also in the inducer. 相似文献
15.
16.
阐述了高温高速离心泵的结构设计和水力设计方法:理论上采用以效率为目标函数的优化水力设计方法;结构上采用复合叶轮和双密封结构,经水力试验和现场运行表明,该泵具有较理想的性能指标和密封可靠性。 相似文献
17.
水泵流量、扬程和功率分别与其转速的一次方、二次方和三次方成正比。对于流量经常变化的场合,采用变频调速技术,控制电机转速,改变泵的流量和扬程,可节约电能50%,显著降低节流损耗,且生产工艺稳定,具有调速性能好、节能效果显著、运行工艺安全可靠等优点。根据运行参数,输送同等流量的水,减少压头损失40m,电流降低约40A,节约用电14kW.h,按目前工业电价0.67元/kW.h计,每年产生直接经济效益8万余元。叶轮切割也是常用的节能技术之一,其技术实施要满足三个条件:水泵实际循环流量满足系统需求,水泵铭牌扬程高于实际扬程5m以上;水泵在装置内所有循环系统主支路调节阀全开时,循环水泵的运行电流超过额定电流;能够降低装置循环系统的阻力。应用叶轮切割技术后,单台水泵工作电流由32A降至30A,一年节电68590kW.h。 相似文献
18.
The possibility of improving the performance of deep well solar pumping systems by using centrifugal pumps with variable rotational speed and modular number of working stages (i.e. Divided Shaft Pump, DSP) was investigated and compared with traditional systems equipped with pumps having a fixed number of stages (i.e Standard Centrifugal Pump, SCP). Starting from commercially available pumps with a given head–mass flow characteristic, a visual simulation tool for the evaluation of the modified DSP pump performance and costs was developed. In principle, it would be possible to use the desired number of modular stages, thus achieving the highest efficiency of the system for all conditions of radiation. In practice, in order to reduce the DSP pump costs to an affordable level, only one shaft breakpoint is suggested (and then two modular blocks of stages), whose optimised position is determined by the simulation program on the basis of insolation curve during the daylight and required head and shaft speed.Referring to a 30 m2 PV system (about 3000 W peak power) and to a well depth of 100 m and considering a commercial 46-stage submersible pump, it was found that a breakpoint at the 31st impeller produced an increase close to 9% of the yearly pumped water yield with respect to a conventional, non-modular pump.For the above system, assuming that the cost of a modified modular pump is 1.5 times higher than that of a standard pump, the payback time varies from 0.5 to 2.5 years when the water sale price ranges between 1.1 and 0.6 €/m3. 相似文献
19.
Seok-Yun Jeon Chul-Kyu Kim Sang-Moon Lee Joon-Yong Yoon Choon-Man Jang 《热科学学报(英文版)》2017,26(2):119-124
This paper presents the performance evaluation of a regenerative pump to increase its efficiency using optimal design method.Two design parameters which defme the shape of the pump impeller,are introduced and analyzed.Pump performance is evaluated by numerical simulation and design of experiments(DOE).To analyze three-dimensional flow field in the pump,general analysis code,CFX,is used in the present work.Shear stress turbulence model is employed to estimate the eddy viscosity.Experimental apparatus with an open-loop facility is set up for measuring the pump performance.Pump performance,efficiency and pressure,obtained from numerical simulation are validated by comparison with the results of experiments.Throughout the shape optimization of the pump impeller at the operating flow condition,the pump efficiency is successfully increased by 3 percent compared to the reference pump.It is noted that the pressure increase of the optimum pump is mainly caused by higher momentum force generated inside blade passage due to the optimal blade shape.Comparisons of pump internal flow on the reference and optimum pump are also investigated and discussed in detail. 相似文献
20.
徐州华美热电公司2×55MW热电厂配备的额定流量为286t/h的锅炉给水泵,运行中暴露出来给水压力富裕量过大,存在着较大的压力节流损失,造成电能浪费等问题,由于电机常处于过负荷状态,影响设备安全。对给水泵的技术改造进行了研究,着重探讨了车削定速给水泵叶轮技改的节能机理,并对其改造方法、改造实例和改造效果进行了分析。 相似文献