Selection of Hot Water Circulating Pump Related Parameters

In multistoried or the high-rise civil constructions the full-time machinery hot water circulation supply system design,whether the design parameters for the flow and the lift of circulating pump are appropriate or not,will be related to continuously,safe,stably running of the hot water supply system.This paper introduces parameter selections of hot water circulating pump both at home and abroad.Based on the difference of these selection means it analyzes the calculating means of the flow and the lift of circulating pump.Whether the circulator flow should join the additional circulating flow or not is the focal point in the argument.In China's present "Code for design of building water supply and drainage" the additional circulating flow is considered not flowing through the circulating pump,so in calculation the additional circulating flow does not contain the circulator flow.By analysis of the water distribution operating mode and various ring circuits difference,as well as considering that for the very small circulator flow it is more difficult to use the valve regulation and to achieve balance between various ring circuits resistance loss,inaccessible absolute circulation in the same regulation,short circuit and so on,the circulator flow should be the sum of circulating flow and additional circulating flow.To calculate lift head the additional circulating flow should be considered through the calculating loop.     

Influence of heat storage mode of domestic hot water on the performance of ground heat exchanger in ground-source heat pump system

The vertical U-tube ground-coupled heat pump system provides cold and heat for the controlling of indoor environment. Under the air-conditioning condition, the vertical U-tube ground-coupled heat pump system with heat recovery can provide domestic hot water. The influence of supplying domestic hot water on the heat transfer performance of ground heat exchangers is different under different operating modes in summer and winter. Through a project design of ground-source heat pump system, the influence of supplying domestic hot water under heat storage mode on the heat transfer performance of ground heat exchangers in summer and winter is respectively analyzed. The dynamic performance of heat exchangers under different working conditions is analyzed, and through numerical calculation, the heat transfer performance parameters of ground heat exchangers under different operating modes are obtained. From the calculation results, the adjusting methods based on the load characteristics of this project represent.     

Approach to the Enhancement of Removal of Phosphorus and Nitrogen in Oxidation Ditch

In response to the characteristic of oxidation ditch and its limitation in removal of phosphorus and nitrogen,the research of the biological phosphorus and nitrogen removal in micro-environment and macroenvironment was reviewed.The process of enhancing phosphorus and nitrogen removal was discussed,the way to improve the phosphorus and nitrogen removal was presented:(1)the proper sequential arrangement of the locations of aerator,influent,effluent and return sludge to form the reversed A~2/O process;(2)forming more rigorously anaerobic zone by means of vertical flow circle;(3)the proper supply of oxygen,to avoid insufficiency of aerobic phosphorus uptake and nitrification with low oxygen supply;While to keep from overmuch waste of carbon source going against de-nitrification,and high oxygen concentration going against anaerobic phosphorus release due to high oxygen supply;(4)the proper hydraulic parameter and oxygen supply mode.     

Calculation Method of Hydraulic Characteristics for Direct-Return Chilled Water System

In order to optimize design and operation, it is necessary to calculate accurately hydraulic characteristics large central air-conditioning systems. Simplified Model can not be applied to hydraulic calculation of large pipe network topological structure for its large calculation error. Taking into account the regulating characteristics of terminal branch temperature regulating valve, a direct-return chilled water system is studied, an accurate mathematical model of pipe network hydraulic characteristics has been established and a computer logic algorithm with virtual flow has been given. A direct-return pipe network with ten AHU branches is used as simulation calculation object, the pipe network supply-return water pressure difference is calculated, and also the temperature regulating valve opening and actual flow of each branch are calculated in the condition of different supply-return water pressure difference. The calculated results accord with the natural characteristics of high pressure difference unbalanced for direct-return pipe network. The calculation method can ensure calculation convergence.     

Discussion on Some Problems Concerning the Building Hot Water Supply System

The problems concerning the patterns of hot water supply and heating equipment, hot water storage equipment volume, water quality and pipe material were studied in this paper. Then, on this basis, the solution for optimizing building hot water supply system was proposed.     

Discussion on Interactive Method for CAD Drawing andCalculation in Building Water Supply and Drainage Design

According to the features of CAD for building water supply and drainage design,the interactive method for CAD calculation and drawing in building water supply and drainage engineering are discussed . A practical example of ADS for hydraulic calculation has been given in this paper .     

考虑渗流和地震时的砂土边坡稳定性计算

基于极限平衡理论,以砂土边坡为研究对象,推导了渗流和地震存在时拟静力法和拟动力法边坡安全系数的计算表达式。通过程序求解,与已有算例对比表明,计算结果基本一致,验证了2种方法解析式的合理性。参数分析表明,水位越高,边坡失稳越严重,水力梯度与安全系数基本为线性关系。渗流方向向下时,稳定性随水力梯度的增加而增大;渗流方向向上时,变化规律相反。水平地震加速度系数对稳定性的影响剧烈,竖向地震加速度系数对稳定性影响较小,简化计算可以忽略不计。最终得出拟静力法的解析式,简单、实用,而拟动力法则可以更为全面地考察砂土边坡稳定性随时间变化的特点。     

负水头灌溉对温室番茄植株蒸腾规律影响的研究

利用Flow32茎流计分别测定负水头灌溉和常规灌溉方式下的番茄植株蒸腾速率,探讨负水头灌溉方式对番茄植株蒸腾影响及植株蒸腾速率与太阳辐射强度之间的关系,同时分析了负水头灌溉下植株一天不同时刻耗水量差异和负水头灌溉对水分利用效率的影响。试验结果表明,负水头灌溉下的番茄植株蒸腾速率要大于常规漫灌,但有着相同的变化趋势,植株的蒸腾速率主要受太阳辐射强度的影响;负水头灌溉方式能为作物适时适量提供水分,且有效地减少无效地表蒸发和地下深层渗漏,提高了作物的水分利用效率。     

Hydraulic Stability of Conditioning-controlling Water-water Ejector Heating Unit in Heating System

The paper introduces an example and its running data of applying conditioning-controlling water-water ejector heating unit developed by the author in heating system. It proves that: the hydraulic stability of the system is very good. When heating medium of heat source and heat consumer are respective high-temperature water and low-temperature water, the hydraulic stability of the heating system is close to 1; when the flow of any consumer of heating network changes, the flow and heating quality of other consumers are almost unchanged.     

Discussion on Water Supply Installation with One Household One Water Meter

Along with the development of commodity economy, the charge way as to record water meters in turns is no more received by the people. It is an important reform in tap water charge system to introduce "one household one water meter" supported by the people. In this paper, several methods of "one household one water meter" installation and water meter level position installation form in details are introduced.A detailed analysis on its development trends and direction is carried out and it is pointed out that the "one household one water meter" installation will develop toward exposed wall and water meter room type level position installation. Finally, the charge way of IC card (TM Card) type and tele-metering water meter computer metering will be applied. This paper analyzes the hydraulic computation of "one household one water meter" and provides the hydraulic condition of "one household one water meter" installation.     

Design and Analysis of the Air Flow and Distribution of Laminated Air Conditioning in Summer in the Powerhouse of Sanxia Hydropower Station

Around the design of air flow and distribution about the laminated air conditioning in summer in the powerhouse of Sanxia hydropower station, the system division, air flow pattern, air supply state and volume etc have been analyzed separately. Based on the existing domestic achievements, the relative calculation model has been established and the application method has been explored. From this the program named as AFDC/LACS has been compiled with language FORTRAN77 and the calculation on the airflow and distribution of the place mentioned above has been done with several design conditions. Thus some batches of the technical parameters have been provided to plan the test conditions in the heat simulated test..     

变流量冷冻水系统温差控制法的适用性

研究了末端设置通断控制阀的一次泵变流量系统在温差控制下的水力特性,并结合风机盘管与房间的非线性换热耦合特性,进一步探讨了温差控制的适用条件以及变温差控制温差值的设定方法。结果表明：末端设置通断控制阀的系统,当管网整体负荷分布均匀且各开启用户的负荷变化规律相近时,温差控制同样是较为适用的,此时系统的水力失调对室内温湿度的影响较小;采用变温差控制时,仅以不同的总负荷率分段设置温差值,并不能获得良好的室内温湿度控制效果,建议以优先保证风盘除湿能力和室内干球温度为原则设定温差值,相比于目前的方法,在同等的室内相对湿度波动下,室内温度的稳定性可以得到保证。     

Feasibility Analysis of Exploitation "City of Hot Spring" in Chongqing

In Chongqing,the South Hot Spring,Small Hot Spring,and West Hot Spring,do not flow automatically;the flux of North Hot Spring and East Hot Spring Have fallen.The geothermal water did not flow through the geothermal water hole of East Hot Spring.However,the exploitation of "city of hot spring" is plan after 5 year.The paper discusses the hydro-geological conditions,the dynamic hot springs and correlativity among hot springs,analyzes the replenishment conditions and capacity of store water,and the correlativity among the exploitation points of "city of hot spring".It shows that the exploitation of "city of hot spring" is feasible.But in order to exploit "city of hot spring" sustain-ably,the whole yield of "city of hot spring" along with should be planned the every hot spring yield in a geothermal water system of anticline.     

Constant Flow Hydraulic System to Variable System for Energy efficiency

This paper analyzed the feasibility of convert the constant flow hydraulic system to variable system in order to realize the regulating of the water flow rate in central air conditioning.The detailed design scheme,which uses transducer and industrial cornputer to implement the hydraulic system energy efficiency controlling for this projiect,is illustrated.The hardware system which uses transducer and computer is connected by RS-485.Software partially uses Visual(C++6.0) to compile the entire procedure.Result of the project proves the energy-saving effect of this control system.     

Experimental and Theoretic Research on Unfree Inundation Water Efflux Flow Field and Circular Field in Rock Salt Well Water-Mining

Simulative experimental research and theoretic analysis on the characteristics of unfree inundation water-flow field and circular field in rock salt well water-mining have been done by glass equipment.The tracer particles spirally circumferentially ascend from bottom to stoma in the triangle vase flow field during the process of unfree inundation efflux flow by positive-cycle pouring water,and the tracer particles fast move up and down in the columnar flow field(jar) as the spouting interval,height of columnar flow field and diameter of the tracer particles are less.While contrary-circular pouring water is done,the water location of centric pipe flow water for the triangle vase is tangential with the down of telescopic pipe and steadily maintains the state.For the columnar flow field,water location is higher than the down of telescopic pipe while the circulation field is just formed and gradually drops until it is tangent with the down of centric pipe.Theory analysis and calculation show that the tracer particles spirally ascend owing to the competition between the up return rate(V_H) and the axial rate(V_m).The fanning orientation of pasting line is the vector sum between V_H and V_m.     

循环水养殖系统水净化装备技术研究

循环水养殖系统为当前水产养殖先进生产力的发展方向,其具养殖水环境高度可控、产品质量安全可靠、节水、节地等特点,符合国家转变经济增长方式,节能减排的战略需求。循环水养殖水净化装备是循环水养殖系统核心组成。其为循环水养殖生产中的水产养殖对象提供良好水生态环境,提高水产养殖品产量及质量,提升资源利用率。本文以循环水养殖系统水净化典型工艺为主线,对其主要环节包括悬浮物去除、溶解性有机物降解、杀菌消毒、增氧、调温等所涉及的装备技术进行探讨及总结,并提出发展建议,以期为精准、高效、节能循环水养殖系统构建,推进其进一步应用提供支持。     

插装式电液比例流量放大阀特性分析

插装阀具有通流量大、结构简单和成本低等优点,广泛应用于液压系统中。笔者针对一种主级基于流量放大原理、先导级采用单级伺服比例方向阀的两级插装比例节流阀特性进行分析,建立了该比例节流阀的简化数学模型,获得了简化条件下的特性关系式。以此为基础,在SimulationX软件环境中建立该液压阀的仿真模型,利用实验数据对模型正确性进行验证,运用验证后的仿真模型对比例阀性能特性进行分析。结果表明：该液压阀输出流量静态特性存在死区,阶跃响应存在时间滞后,主阀流量放大倍数并不是常数,性能影响因素与主阀反馈槽预开量、面积梯度、级间过渡容腔体积以及先导阀通流能力等相关。     

水流对鱼类游泳行为和生理代谢的影响的研究进展

为掌握适合鱼类生长的水流条件,对国内外现有的鱼类在不同水流条件下的行为特征及生理代谢进行了系统性的回顾,分析了水流对水质的影响,对比了不同鱼类受水流刺激导致的行为上的差异,并从鱼类生理代谢角度分析了水流对鱼类的影响。结果表明：鱼类能够承受的最大流速一般与体长(Body length, BL)有关,较低的水流速度(<0.5 bl/s)对鱼类无显著性影响,较高的水流速度(>2 bl/s)对鱼类的行为、存活率和生理代谢产生较大的负面影响,而中等的水流速度(0.5～2 bl/s)适合鱼类的生长,能够提高鱼体免疫力,增强鱼体抗氧化水平。针对当前鱼类耐受流速的研究进行展望,从实验角度进行优化,以期获得更加准确的生长-流速曲线。     

Opening Flow Coefficient and its Effect on Fire Smoke Flow

The flow coefficient of the typical doors and windows in different states between opening and closing was tested in a high rise experimental fire tower. It can be used for the prediction calculation of the fire smoke flow and the calculation of the positive air supply as well as for the ventilation. Using the prediction software of the fire smoke flow properties in the building, the effect of the flow coefficient on the fire smoke flow was also studied.     

被征地农民留用地安置方式的特征与模式分析

被征地农民的留用地安置方式自20世纪80年代初开始探索性尝试以来,已在中国东中部地区部分经济发展较快,用地需求矛盾突出的城市中推行,在取得一定成绩的同时也产生了巨大的争议,在实施过程中面临适用范围有限、规划协调难度较大、权属复杂、管理难度大等问题。结合调研实例,在留用地安置特征提取的基础上,对中国已开展的留用地实践进行了模式划分,并就此制度的规范发展提出政策建议。