一种新的分布式水泵供热布置方案分析

供热管网的用户端应用分布式水泵代替阀门来调节水力工况有助于节约水泵能耗。在比较单热源枝状管网采用传统阀门调节和分布式水泵调节供热方案的水力工况和节能性能的基础上,提出一种新的分布式水泵供热布置方案。通过理论及案例分析了多热源环状管网应用这一新方案下的变工况水力调节性能、水温稳定性能及节能性能。结果表明,新的分布式水泵布置方案有利于降低供热系统的功耗、减缓用户水温波动,并具有供热质与量的调节相对独立、调节控制策略简便的特点。     

Deformation control method of a large cross-section tunnel overlaid by a soft-plastic loess layer: a case study

This paper presents a case study of a large cross-section high-speed railway tunnel overlaid by a Q₂ soft-plastic loess layer. Due to poor engineering properties of the soft-plastic loess, two unexpected collapses occurred. This indicates that there is great difficulty and risk during tunneling. In this paper, the deformation control methods are studied by carrying out a series of numerical simulations and then validating via field tests. The stress and seepage coupling equations are deducted to embed into a 3D fluid-mechanical coupled numerical analysis. The results show that the curtain grouting scheme can effectively control the deformation of surrounding rock, and the real field data of settlement and horizontal convergence are 152 mm and 37 mm, respectively. However, the tunneling advance rate is slow (0.6 m/day) in trial sections because of the mutual interference between construction procedures. It can be used as an alternative scheme for lager deformation. The advanced drainage scheme can lower the ground water table below the excavation outline. The average water content of soft-plastic loess decreases from 26 to 22%, and the state of surrounding rock changes from soft plastic to hard plastic. The in situ settlement and horizontal convergence are 165 mm and 51 mm, respectively. Finally, it is proposed to use advanced drainage in combination with advanced small pipe grouting as a follow-up construction scheme. The successful completion of the whole tunnel proved the effectiveness of the proposed method.

     

机械排烟与水喷淋对淮南某电影厅火灾人员疏散影响的模拟研究

作为人们休闲生活的重要场所,电影厅内人员集中、内部装修和装饰使用大量易燃材料、电器设备线路复杂,存在不少安全隐患。电影厅火灾对人民群众的生命财产安全构成了重大威胁,本文借助FDS火灾模拟软件,建立了有无机械排烟、有无水喷淋装置共4种工况的模型,对淮南某电影厅火灾时的烟气运移规律和温度变化情况进行了模拟。分析模拟结果可知,机械排烟设施对火灾烟气控制有一定的效果,水喷淋装置对抑制火灾与烟气的蔓延效果更为显著,机械排烟设施与水喷淋装置共同作用可有效抑制烟气的扩散及温度的升高,延长逃生时间。同时,理论计算可知火灾发生时所需要的安全疏散时间为151.4 s。最后,在上述分析的基础上,提出了有效的防火设计方案,为此类公共场所的消防管理决策提供有力依据。     

Application of RMR and Q geomechanical classification systems along the proposed Mujib Tunnel route, central Jordan

This paper highlights the engineering geological investigations that have been carried out along the proposed Mujib Tunnel. The geomechanical classifications – rock mass rating (RMR) and Q index for tunnelling purposes – have been used to categorize the rock mass along the proposed tunnel. This tunnel will be driven into the Cambrian Sandstones (Um Ishrin Sandstone Formation) which are characterized by two to three sets of structural discontinuities. The geotechnical information obtained from drilled boreholes as well as from surface discontinuity mapping using scanline techniques indicates fractured sandstone along the proposed tunnel. This would be classified as very poor to fair quality material using the Q indexand RMR values. An expert system was used to obtain the design parameters of the proposed tunnel and to determine the support requirements. Electronic Publication     

The Avalon Lakes: An Environmental Opportunity

The Avalon Lakes project was a concept to utilize, as water storage reservoirs, shallow basins left by commercial peat exploitation. There are, however, important nature-conservation interests in the project area. The proposed scheme ultimately incorporated measures to enhance these and, perhaps unusually for a source development, was broadly supported by conservation groups. The related cost was estimated at £4.2M, or 17% of the overall source works'price.
Plans and scientific investigations of the scheme occupied a span of 21 years to 1988. It was eventually abandoned as an option for future water supplies following the restructuring of Wessex Water Authority in preparation for privatization of the water industry. The grounds for terminating the project were substantially concerned with costs, though coloured by lingering apprehension about the consistency of water quality.
There is now a greater public awareness of the adverse environmental effects of water resource developments. It is suggested that this will lead to future schemes, less obviously suited to their surroundings than Avalon, incurring a higher conservation-related cost in order to gain acceptance.     

The Blashford Lakes Water Supply Scheme

Wessex Water has developed a new 35 Ml/d water supply source, using lakes formed from worked-out gravel pits, to meet increasing demands for water and to provide security for existing supplies.
Having identified the need for the scheme, an engineering feasibility study was carried out in conjunction with a full environmental assessment. This led to the successful promotion of the Stage I scheme in 1986. Design and construction took place immediately after, and the scheme was officially opened in 1989.
There are opportunities to expand the scheme as more lakes are formed by gravel working, and proposals for this are well advanced. This paper describes all the key elements in the promotion and development of the scheme.     

内廊式建筑空调末端设计方案讨论

结合实际工程，指出传统的风机盘管加新风系统空调末端设计方案即单干管双侧供水送风存在的问题，提出了改进的双干管单侧供水送风方案。     

A multi-step computation scheme: Decoupling kinetic processes from physical transport in water quality models

This paper presents a computation scheme that considers accuracy and efficiency in the numerical treatment of the kinetic processes in water quality models. The proposed scheme involves decoupling of physical transport and kinetic processes in the governing mass-balance equations. The decoupled equations are solved by employing multi-step computation, in which the kinetic processes are applied for the first half time step, followed by the physical transport for a full time step, and the kinetic processes are applied again for the remaining second half time step. The kinetic equations are solved numerically or analytically, which may require prior linearization of the equations. The numerical solution scheme of the kinetic equations alternates between explicit and implicit schemes, and is equivalent to the second-order accurate Crank-Nicolson solution. A hypothetical model, which is simple enough to have an analytical solution, is used to explain the concept, and to demonstrate the accuracy and computational efficiency of the proposed scheme. The proposed scheme and three other traditional solution schemes are compared to the analytical solution. The proposed scheme shows better accuracy and computational efficiency compared to other schemes.     

上海某深基坑工程承压水抽水试验分析

以上海某深基坑工程为例,通过承压水抽水试验确定出水量和承压含水层的水位下降与时间的关系以及承压含水层的水文地质参数,为设计该深基坑承压水抽水方案和基坑开挖施工方案奠定了基础。     

某江水源热泵取水方案选择及取水泵房设计

本文以重庆武隆某江水源热泵工程为例,对干式江水直接取水+水处理和潜水泵取水方案进行比较分析,优选出潜水泵取水方案;并对其取水泵房的布置、水处理方案及设备检修与安装固定进行设计分析。     

国内某地铁加装细水雾灭火系统方案

对行业内自动灭火系统进行对比,提出细水雾灭火系统在城市轨道交通车辆上应用的优势。通过在国内某地铁加装细水雾灭火系统的实例,介绍了细水雾灭火系统的方案、系统组成及细水雾装置的配置方案,依据地方标准的要求,通过对灭火时环境参数的分析,验证了加装的细水雾灭火系统达到了设计要求,起到了灭控火的目的。     

换流变压器消防设计研究

基于新型火灾探测技术、新型水系灭火剂的水喷雾和消防炮灭火技术,搭建换流变压器模拟试验平台,开展不同场景下的火灾探测及灭火试验研究。研究表明,对于换流变压器火灾,新型火灾探测器可快速响应,基于水系灭火剂的水喷雾及消防炮可快速扑灭并可高效降温。根据研究成果并结合项目实际情况,提出一套适用于换流变压器的消防设计方案。     

Creating a Wetland Using Rainwater as Mitigation for Loss of Waterfowl Habitat

A major onshore hydrocarbon terminal was constructed on coastal fields at Point of Ayr on the Welsh side of the Dee Estuary which is protected under national and international environmental legislation and conventions as a wetland of major importance - especially for birds. A scheme is described which was implemented to increase the carrying capacity for waterfowl in an area of farmland adjacent to the terminal. The main method for enhancing the habitat involved bringing a core area of the farm to 'field capacity'(saturation with water) by surface wetting. Various potential water sources for the scheme were explored. The chosen system entailed the collection of rainwater runoff in a system of drains and reservoirs during the winter and the distribution of the water to bunded irrigation areas in the following autumn. The early successes of commissioning experiments are briefly described, and the key issues for further investigation are identified.     

Identification and Adaptive Control for Open Channel Water Flow Systems

Abstract: Despite the continuous advances in the control design for water flow systems such as irrigation and sewer systems, the design and deployment of efficient water flow control systems requires a careful and efficient fine‐tuning of their parameters prior and during the actual system operation. In the majority of water flow control applications, the controller design is based on simplified models (e.g., linear models assuming a fixed time‐delay) for the water flow dynamics and as a result the initial controller design calls for a major fine‐tuning at the initial deployment of the control system; moreover, the frequent changes in water management commands/needs as well as the severe exogenous disturbances call for a continuous update of the controller parameters. Conventional controller tuning approaches cannot be used for the efficient tuning of the controller parameters in water flow control systems, mainly due to the highly nonlinear dependence of the time‐delay with respect to the water flow. In this article, we first introduce and analyze both by means of mathematical analysis and simulation experiments, a computationally simple and efficient methodology for the identification of water flow system dynamics as a State‐dependent Delay Difference Equation (sdDDE) model. The main advantage of this methodology is that it can explicitly identify the nonlinear relationship between the water flow system states and the system time‐delay. Then, we show that such an sdDDE identification scheme can be used for the efficient adaptive tuning of a general class of water flow control systems. More precisely, by exploiting the knowledge—obtained using the sdDDE identification scheme—regarding the nonlinear characteristics of the time‐delay, we come up with a convergent adaptive control scheme, which is able to quickly track rapid changes in setpoint commands and efficiently attenuate severe exogenous disturbances. Simulation results demonstrate that the proposed scheme out‐performs significantly existing well fine‐tuned linear and nonlinear control schemes.     

A direct load control strategy of centralized air-conditioning systems for building fast demand response to urgent requests of smart grids

When receiving an urgent request from a smart grid, shutting down part of operating chillers directly in the air-conditioning system in a building can achieve immediate power reduction. However, no study has addressed how to determine the number of chillers/pumps to be shut down and how to regulate the load of retained equipment systematically during DR events. This paper presents a new approach to address these issues based on three schemes. A power demand optimization scheme predicts the building cooling demand and the power limiting threshold in response to a received DR request. A system sequence control resetting scheme determines the number of operating chillers/pumps to be retained. An online control/regulation scheme ensures the system power following the expected profile by regulating the total chilled water flow delivered to the building and therefore the chiller load. It also employs a cooling distributor to distribute chilled water to individual zones concerning different sensitivities/sacrifices to temperature increases. Case studies are conducted on a simulated dynamic building air-conditioning system. Results show that, during DR events, the proposed strategy can achieve the expected power reduction (i.e., about 23%) and also maintain acceptable zone temperature even though uncertainties exist in the prediction process.     

大海波水库输水方式选择

结合大海波水库输水现场的地形地质条件,对输水方式进行了研究,提出了三种输水方案,同时对各方案进行了阐述,分析了各种方案的经济性,通过比较,推荐采用方案二输水方式进行取水。     

Review of the technological approaches for grey water treatment and reuses

Based on literature review, a non-potable urban grey water reuse standard is proposed and the treatment alternatives and reuse scheme for grey water reuses are evaluated according to grey water characteristics and the proposed standard. The literature review shows that all types of grey water have good biodegradability. The bathroom and the laundry grey water are deficient in both nitrogen and phosphors. The kitchen grey water has a balanced COD: N: P ratio. The review also reveals that physical processes alone are not sufficient to guarantee an adequate reduction of the organics, nutrients and surfactants. The chemical processes can efficiently remove the suspended solids, organic materials and surfactants in the low strength grey water. The combination of aerobic biological process with physical filtration and disinfection is considered to be the most economical and feasible solution for grey water recycling. The MBR appears to be a very attractive solution in collective urban residential buildings.     

某电厂河床式取水与泵船取水方案比较研究

根据拟建工程厂址的水文条件和取水岸线的地形资料,对河床式取水构筑物方案与泵船取水的方案进行了综合比较,推荐出了合理、安全且经济适用的补给水系统取水方案,为今后国内外类似工程的设计提供参考。     

天津市某宾馆建筑节能改造方案分析

以天津市某宾馆建筑为研究对象,对宾馆建筑用能存在的问题进行了探讨,提出了从围护结构、供暖空调系统、生活热水供应、动力照明系统及行为管理上进行节能改造的方案。