Applied Mechanics and Materials Vols. 353-356

Abstract: Water distribution system is one of the most critical facilities in cities, and is more fragile compared with other structures. Losses in a water distribution system are often existed before health monitoring is implemented. This paper proposes to detect an existing local loss in a water distribution system on the basis of optimal monitoring of water pressure. The local loss is assumed at different positions with different extents, and pressures at monitoring stations is calculated, and the loss is then detected by minimizing the difference between the calculated and monitoring pressures at the monitoring stations. The efficiency is validated by example analysis. It is shown that an existing local loss is more reliably detected in a water distribution system with optimal monitoring.

Abstract: In order to determine the reasonable construction scales of the water supply projects in rural areas, in this paper, we firstly analyzed the major influencing factors to safe water supply projects construction scale. Secondly we respectively establish correlation equations between scales and water works construction cost, pipeline network cost and running cost. Further, with the correlation equations we propose an optimal model for projects construction scale and suggest a water supply projects construction scales optimization analysis methods in rural area based on GIS & GA. Finally the model and methods are used in Jiaonan rural area in Qingdao, and obtained the optimal solution also the economic reasonable water supply projects scale of this rural area.

Abstract: On the basis of the traditional linear programming model,this paper presents a optimal design mathematical model of gravity branch distribution network. Considering the coupling constraint, the model takes the length of main and subordinate pipe having standard diameter as decision variables. The minimum works investment is taken as objective variable, and the MATLAB is used to solve. There are a better result in the optimal design of branch distribution network with this method in the application cases, and which can provide a basis for the rural drinking water safety project.

Abstract: Nowadays, the demand of people for urban water supply security is increasing. Meanwhile, the scale of water supply system is expanding and the topology is being more and more complicated. Aiming at these problems above, the technology of simulation modling and software development for urban water supply network is researched in this article. First of all, through studying the parameter testing technique, the load and change law of water consumption, the pressure distribution law, and the actual conveyance capacity of main pipes of the whole water supply network are accurately mastered. Correspondingly, the simulation database is built. On this basis, aiming at scientific operation and water quality protection, taking opening territorial water supply network of one city for example, the microscopic hydraulic model of water supply network of this area is built, meanwhile, the simulation analysis platform is developed, with the application of on-line monitoring technology. The platform which has well expansibility and utility has been applied to water supply network of an urban city.

Abstract: Through comparing and analyzing domestic and foreign research on soil infiltration in recent years, this article summarizes the research progress on soil infiltration, especially the innovation in theory, method and progress in practical use and gives the advantages and disadvantages among various methods. It can provide reference for the researchers engaged in the study of soil infiltration and efficient soil water utilization.

Abstract: The Ziquejie Terrace is one of the earliest cultivated terraces in the world, so it has important theoretical and practical significance to study its water culture for the protection and development. By on-the-spot investigation, interview and literature review, this paper reduces the Ziquejie terraces water culture as follows: efficient use of water resource, consciousness of water resource protection and scientific and reasonable irrigation area planning and management. At present, there are many problems existing in the Ziquejie Terrace area, such as soil and water erosion, runoff reduction and the shortage of irrigation water, environmental disruption caused by tourism development, terraced collapse, water culture facing destruction and other issues. To solve these problems, the paper proposed to study the contradictions between ecological protection and tourism development, between irrigation construction and water culture, and gived protection strategies.

Abstract: In order to investigate natural cross-ventilation in buildings, computational fluid dynamics (CFD) with the DES model is applied. The aim of this paper is to investigate the influence of surrounding buildings on natural ventilation in target building under different separation distances. The simulation results indicate that surrounding buildings has a significant impact on airflow structure and airflow rate of the target building. The flow characteristics in target building is determined by the flow regime in street canyon.

Abstract: Combining the experimental teaching in polytechnic, the room temperature distribution of the experimental classroom in summer was analyzed by temperature measure and computer simulation. The results provide the foundation for the rationalization distribution of experimental equipment, person and air conditioner in experimental classroom. It helps to optimize teaching environment, reduce energy wastage, and avoid the hidden trouble bringing by hot summer.

Abstract: In order to investigate natural cross-ventilation in buildings driven by combined wind and thermal buoyancy forces, computational fluid dynamics (CFD) with the DES model is applied. The aim of this paper is to investigate the influence of thermal buoyancy force on natural ventilation in buildings under different heating conditions. The simulation results indicate that the thermal effect has a significant impact on airflow structure and airflow rate of building at low Froude numbers, however, the thermal effect can be neglected when Froude number value is greater than 6.

Abstract: To study the relation between the heat load ratio of the external wall and window to the total heat load and the indoor heat comfortability index PMV, putting up the numerical calculation to a radiator heating room. It gains the value of the PMV when the heat load ratio of the external wall and window to the total heat load is separately 0.2 and 0.8, 0.3 and 0.7, 0.4 and 0.6, 0.5 and 0.5, 0.6 and 0.4. And it draws the curve about the PMV and the different heat load ratio of the external wall and window to the total heat load. The curve shows that when the heat load ratio of the external wall and window to the total heat load is 0.4 and 0.6, the indoor heat comfortability index PMV is maximal.