Seismic performance evaluation of water supply pipes installed in a full-scale RC frame structure based on a shaking table test

As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame structure.Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance.Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical simulation.The acceleration response and displacement response of different combinations are compared.The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.

Calculation of Mass Concrete Temperature Containing Cooling Water Pipe Based on Substructure and Iteration Algorithm

Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and engineering.One such equation is the Fourier equation,which is a commonly used and effective method for evaluating the effectiveness of temperature control measures for mass concrete.One important measure for temperature control in mass concrete is the use of cooling water pipes.However,the mismatch of grids between large-scale concrete models and small-scale cooling pipe models can result in a significant waste of calculation time when using the finite element method.Moreover,the temperature of the water in the cooling pipe needs to be iteratively calculated during the thermal transfer process.The substructure method can effectively solve this problem,and it has been validated by scholars.The Abaqus/Python secondary development technology provides engineers with enough flexibility to combine the substructure method with an iteration algorithm,which enables the creation of a parametric modeling calculation for cooling water pipes.This paper proposes such a method,which involves iterating the water pipe boundary and establishing the water pipe unit substructure to numerically simulate the concrete temperature field that contains a cooling water pipe.To verify the feasibility and accuracy of the proposed method,two classic numerical examples were analyzed.The results showed that this method has good applicability in cooling pipe calculations.When the value of the iteration parameterαis 0.4,the boundary temperature of the cooling water pipes can meet the accuracy requirements after 4∼5 iterations,effectively improving the computational efficiency.Overall,this approach provides a useful tool for engineers to analyze the temperature control measures accurately and efficiently for mass concrete,such as cooling water pipes,using Abaqus/Python secondary development.

Selection of Water Transmission Method and Analysis of Pipe Network Zoning in Municipal Water Supply and Drainage Design

With the acceleration of urbanization,the demand for water supply and drainage pipe networks has increased significantly.In the planning of urban construction,it is necessary to optimize the design of the water supply and drainage system pipe network to effectively save energy while providing residents with more accessible water resources.Therefore,the municipal water supply and drainage system and the water transmission methods should be designed according to the geographical conditions of the city.In this paper,we mainly analyze the design of municipal water supply and drainage systems and the selection of water transmission methods.Besides,the optimization of the water supply and drainage network zoning process and pipe network maintenance is also discussed,so as to provide a reference for municipal water supply and drainage work.

Analysis of Municipal Water Supply and Drainage Pipe Design Technology

The quality and safety of residents’water rely heavily on the design of municipal water supply and drainage pipes.Therefore,this paper aims to enhance the optimization of municipal water supply and drainage pipe design by focusing on design requirements,principles,and key elements.Drawing from relevant design optimization experiences,technology advancements,and optimization measures,the research will analyze and consolidate the essential aspects of municipal water supply and drainage pipe design.The goal is to fundamentally elevate the quality standards of these designs,ensuring they meet the criteria for engineering project excellence.Through this comprehensive approach,we aim to contribute to the improvement and sustainability of water supply and drainage systems,safeguarding the well-being of residents.

Application of water loop variable refrigerant flow air-conditioning system in large-scale buildings in northern China

A water loop variable refrigerant flow（WLVRF）air-conditioning system is designed to be applied in large-scale buildings in northern China.The system is energy saving and it is an integrated system consisting of a variable refrigerant flow（VRF）air-conditioning unit,a water loop and an air source heat pump.The water loop transports energy among different regions in the buildings instead of refrigerant pipes,decreasing the scale of the VRF air-conditioning unit and improving the performance.Previous models for refrigerants and building loads are cited in this investigation.Mathematical models of major equipment and other elements of the system are established using the lumped parameter method based on the DATAFIT software and the MATLAB software.The performance of the WLVRF system is simulated.The initial investments and the running costs are calculated based on the results of market research.Finally,a contrast is carried out between the WLVRF system and the traditional VRF system.The results show that the WLVRF system has a better working condition and lower running costs than the traditional VRF system.

Application of Dynamic Programming Method in Optimization of Water Distribution Pipe Network

With a water-supply network by dynamic programming. The minimal as an example, the network was optimized annual discounted costs were taken as an objective function and node pressure etc. as constraint conditions. The alternative pipe diameters were optimized as per enumeration method and the group allowing objective function with the least values would be the optimized one. It is proved the optimized pipe network reduced by 11.49% in terms of cost and the optimized ben- efits proved much significant.

Analysis on Shock Wave Speed of Water Hammer of Lifting Pipes for Deep-Sea Mining

Water hammer occurs whenever the fluid velocity in vertical lifting pipe systems for deep-sea mining suddenly changes. In this work, the shock wave was proven to play an important role in changing pressures and periods, and mathematical and numerical modeling technology was presented for simulated transient pressure in the abnormal pump operation. As volume concentrations were taken into account of shock wave speed, the experiment results about the pressure-time history, discharge-time history and period for the lifting pipe system showed that： as its concentrations rose up, the maximum transient pressure went down, so did its discharges; when its volume concentrations increased gradually, the period numbers of pressure decay were getting less and less, and the corresponding shock wave speed decreased. These results have highly coincided with simulation results. The conclusions are important to design lifting transporting system to prevent water hammer in order to avoid potentially devastating consequences, such as damage to components and equipment and risks to personnel.

Simulation investigation on fluid characteristics of jet pipe water hydraulic servo valve based on CFD

Simulation investigation on fluid characteristics of the water hydraulic jet pipe servo valve （WHJPSV） is conducted through a commercial computational fluid dynamics （CFD） software package FLUENT. In particular, the factors to fluid characteristics of WHJPSV are addressed, which include diameter combination of jet pipe and receiver pipe, jet pipe nozzle clearance, angle between two jet receiver pipes and deflection angle of the jet pipe. It is concluded from the results that： （i） Structural parameters have great influences on fluid characteristics of WHJPSV, when d1 = d2 = 0.3 mm, α= 45 , b = 0.5 mm, and the simulation exhibits better fluid characteristics; （ii） The magnitude of the recovery pressure and flow velocity increase almost linearly with the deflection angle of jet pipe. The research work in this paper is important for determining and optimizing the structural parameters of the jet pipe and jet receiver. The relevant conclusions could be extended to the study of other water hydraulic servo control components.

Optimal operation of water distribution networks under local pipe failures

The optimal operation of water distribution networks under local pipe failures, such as water main breaks, was proposed. Based on a hydraulic analysis and a simulation of water distribution networks, a macroscopic model for a network under a local pipe failure was established by the statistical regression. After the operation objectives under a local pipe failure were determined, the optimal operation model was developed and solved by the genetic algorithm. The program was developed and examined by a city distribution network. The optimal operation alternative shows that the electricity cost is saved approximately 11%, the income of the water corporation is increased approximately 5%, and the pressure in the water distribution network is distributed evenly to ensure the network safe operation. Therefore, the proposed method for optimal operation under local pipe failure is feasible and cost-effective.

Investigation of the Leaching Behavior of Mortar Pipe Lining in Drinking Water

The leaching behavior of three types of mortars was investigated using a self-design device which could simulate the field conditions of pipe lining. The results by ICP and ESEM measurement show that the developed slag cement mortar is suitable for the lining of cast iron pipe that is used for delivering drinking water.

New design solutions for low-power energy production in water pipe systems

This study is the result of ongoing research for a European Union 7th Framework Program Project regarding energy converters for very low heads, and aims to analyze optimization of new cost-effective hydraulic turbine designs for possible implementation in water supply systems （WSSs） or in other pressurized water pipe infrastructures, such as irrigation, wastewater, or drainage systems. A new methodology is presented based on a theoretical, technical and economic analysis. Viability studies focused on small power values for different pipe systems were investigated. Detailed analyses of alternative typical volumetric energy converters were conducted on the basis of mathematical and physical fundamentals as well as computational fluid dynamics （CFD） associated with the interaction between the flow conditions and the system operation. Important constraints （e.g., size, stability, efficiency, and continuous steady flow conditions） can be identified and a search for alternative rotary yolumetric converters is being conducted. As promising cost-effective solutions for the coming years, adapted rotor-dynamic turbomachines and non-conventional axial propeller devices were analyzed based on the basic principles of pumps operating as turbines, as well as through an extensive comparison between simulations and experimental tests.

Effect of Pipe Diameter on Electrochemical Behavior of Stainless Steel Type 304 Pipes in Tap Water

We investigated the effects of pipe diameter on the corrosion resistance of stainless steel type 304 pipes using electrochemical measurements. Compared to plate steel, pipes have harder physical properties and tend to be harder and showed greater permeability with decreasing inner diameter. We found that the maximum corrosion current density in the secondary active state, which is the starting point of secondary passivation, appeared in the polarization curve measurement in tap water. Similar to the Vickers hardness and the maximum current density in the secondary active state, the permeability tended to increase as the diameter decreased. This is thought to increase the amount of deformation-induced martensitic and increase corrosion susceptibility. The peak of the secondary active current density was clearly seen as the potential sweep speed was increased. In addition, potential sweep speed dependence was observed in the corrosion susceptibility evaluation of deformation-induced martensite. In comparison with acid treatment, the formation of deformation-induced martensite was considered to occur in the extreme surface layer. The maximum corrosion current density in the secondary active state is expected to be a new susceptibility evaluation method for evaluating the deformation-induced martensitic transformation.

Analysis on Buckling Performance of Submarine Pipelines During Deepwater Pipe-Laying Operation

Pipes inevitably encounter high ambient pressure and bending moment during the deepwater pipe-laying process,which can lead to elliptical buckling and even deterioration failure.For the safety of pipe-laying operation,available formulas for the pipe stability are established on the basis of the assumption of uniform deformation along the tube length and symmetrical buckling.This method can predict the nonlinear response of elliptical collapse of steel circular tubes for different ratios of diameter to thickness（D/t）under pure bending or combined bending and external pressure.In these formulas,the strain-displacement relationship is deduced from the nonlinear ring theory,and the Ramberg-Osgood constitutive model is applied to simulate the inelastic material behavior.Meanwhile,the principle of virtual work is adopted to derive the equilibrium equations.A set of equations is solved by the Newton-Raphson method,and the iterative scheme contains nested iteration for the constitutive relation.In order to check the effectiveness of this theoretical method,illustrative examples are presented in this paper.Besides,the numerical simulation is carried out by use of ANSYS.A comparison of the results shows that the theoretical method can provide reasonable prediction for engineering practice.

Health Safety of Main Water Pipe Materials Supplied in China Market

Objective To assess the health safety of copper, steel and plastic water pipes by field water quality investigations. Methods Four consumers were randomly selected for each type of water pipes. Two consumers of every type of the water pipes had used the water pipes for more than 1 year and the other 2 consumers had used the water pipes for less than 3 months. The terminal volume of tap water in copper and steel water pipes should be not less than 0.1 liter, whereas that in plastic water pipes should be not less than 1 liter. Results The mean values of the experimental results in the second field water quality investigation of the copper and steel water pipes met the Sanitary Standards for Drinking Water Quality. The items of water sample of the plastic water pipes met the requirements of the Sanitary Standards for Drinking Water Quality. Conclusion Copper, steel, and plastic pipes can be used as drinking water pipes.

Thermal field in water pipe cooling concrete hydrostructures simulated with singular boundary method

The embedded water pipe system is often used as a standard cooling technique during the construction of large-scale mass concrete hydrostructures. The prediction of the temperature distribution considering the cooling effects of embedded pipes plays an essential role in the design of the structure and its cooling system. In this study, the singular boundary method, a semi-analytical meshless technique, was employed to analyze the temperature distribution. A numerical algorithm solved the transient temperature field with consideration of the effects of cooling pipe specification, isolation of heat of hydration, and ambient temperature. Numerical results are verified through comparison with those of the finite element method, demonstrating that the proposed approach is accurate in the simulation of the thermal field in concrete structures with a water cooling pipe.

THEORETICAL ANALYSIS OF USING AIRFLOW TO PURGE RESIDUAL WATER IN AN INCLINED PIPE

A refined theoretical analysis for using the spiral airflow and axial airflow to purge residual water in an inclined pipe was presented. The computations reveal that, in most cases, the spiral flow can purge the residual water in the inclined pipe indeed while the axial flow may induce back flow of the water, just as predicted in the experiments presented by Horii and Zhao et al. In addition, the effects of various initial conditions on water purging were studied in detail for both the spiral and axial flow cases.

Experimental Study of Energy-Saving Air-Conditioner with Hot Water

Energy-saving air-conditioner with hot water is an air source heat pump air-conditioner,which can also supply hot water.The hot water is heated by a double pipe condenser connected with an air-cooled condenser in series in the system.This experiment of the energy-saving air-conditioner was carried out in the enthalpy-difference air-conditioner laboratory.The hot water temperature and the compressor's discharge and suction pressure were recorded in the working condition,where the ambient temperature was at 43 ℃,35 ℃,21 ℃,7 ℃,and 2 ℃ separately.The results showed that the system operated stably and reliably.This system can supply 240 L hot water at 50 ℃ in the whole year,and its coefficience of performance(COP)is much higher than the conventional air source heat pump system.Its energy conservation was proved by comparing the thermal efficiency with other sourece water heaters.

Analytic study on the optimal control of water hammer waves in pipes

To realize the accurate control of water hammer in pipes by valve stroking, based on basic differential equations of water hammer subjected to initial and boundary conditions, the traveling solution of wave equations in finite region was applied to the linear water hammer problem. With the given velocity function at the valve and the introduction of curve integration independent of integral path, the exact analytic solution of dimensionless water hammer pressure was obtained in the course of valve closing. Based on the definition of eigen wave height, optimal eigen wave height and observation time, the control goal of water hammer pressure and the judgment rule of the optimal eigen wave height were determined, then the optimal velocity function in the calculated example was derived, which can reduce the water hammer pressure maximally. According to this function, a valve closing program was set, and the optimal control of water hammer could be realized.

Evaluate the Possibility of Cracking Pipe on Water Supply Network under the Age of Pipe

Minimizing water loss in water supply networks is one of the objectives for protecting water resources. Currently, the large amount of water loss is mainly due to leakage of the pipeline network. The leaking of pipe can be caused by incorrect construction, impacted by external forces, or corroded pipe material and aging. Therefore, to control and predict the cracking area on pipe, it is necessary to collect data about pipe conditions, approve the solution of technology improvement and define the ability of pipe capacity from setting up to the first preparing time. This paper will demonstrate how to evaluate corrosion pipe under the age of pipe and the impact level of internal pressure pipe at different times, and will put forward solution of effective leaking management on water supply network.

Computational Fluid Dynamics Study on Water Flow in a Hollow Helical Pipe

Although curved pipes are used in a wide range of applications, flow in curved pipes is relatively less well known than that in straight ducts. This paper presents a computational fluid dynamics study of isothermal laminar single-phase flow of water in a hollow helical pipe at various Reynolds numbers. The ranging of Reynolds numbers of fluid was from 703.2 to 1687.7. The three dimensional governing equations for mass and momentum have been solved. It was found that with increasing Reynolds number and creation of centrifugal forces, a high velocity and pressure region occurs between two tubes, at the outer side of the hollow helical pipe walls. Friction factor decreases as the tendency for turbulence increases.