Hydraulic Pipe Research Articles

Dynamic Characteristic Analysis for Fluid-Conveying Pipe of TBM

Aiming at the influence of the strong vibration generated in the working process of the full-section hard rock tunneling machine on the response characteristics of the hydraulic straight pipe, according to the fluid-solid coupling theory and forced vibration theory, the transverse motion mathematical model of the straight pipe under the basic vibration was established. The model was solved by Galerkin method, and the correctness of the model was verified by experiments. The influence of foundation vibration parameters and fluid velocity on the response characteristics of straight pipe is analyzed by simulation. It is found that the vibration amplitude of straight pipe increases with the increase of foundation vibration amplitude and foundation vibration frequency. The higher the foundation vibration frequency, the smaller the liquid velocity is when the straight pipe resonates. At the same time, the working failure areas of straight pipe under different dimensionless velocity and fluid-pipe mass ratio are obtained. The research provides some theoretical basis for the vibration resistance design of TBM direct pipeline.

Analysis of a Hydraulic Pipe System with Major and Minor Pressure Losses

Analysis of a Hydraulic Pipe System with Major and Minor Pressure Losses

Influence of spring-mass systems on frequency behavior and critical voltage of a high-speed rotating cantilever cylindrical three-dimensional shell coupled with piezoelectric actuator

In this article, vibrational behavior and critical voltage of a spinning cylindrical thick shell covered with piezoelectric actuator (PIAC) carrying spring-mass systems are investigated. It should be noted that, the installed sensors on the proposed systems are considered as a tip mass. This structure rotates about axial direction and the formulations include the Coriolis and centrifugal effects. In addition, various cases of thermal (uniform, linear, and nonlinear) distributions are studied. The modeled cylindrical thick shell covered with PIAC, its equations of motion, and boundary conditions are derived by the principle of minimum total potential energy and based on a new three-dimensional refined higher-order theory (RHOST). For the first time in the present study, attached spring-mass systems have been considered in the rotating cylindrical thick shells covered with PIAC. The accuracy of the presented model is verified compared with previous studies. The novelty of the current study is consideration of the applied voltage, rotation, various temperature distributions and spring-mass systems implemented on the proposed model using the RHOST. The generalized differential quadrature method is presented to discretize the model and to approximate the governing equations. In this study the simply supported conditions have been applied to edges and cantilever (clamped-free) boundary conditions have been studied in x = 0, L, respectively. The results show that, applied voltage, angular velocity, temperature changes and spring-mass systems play an important role on the critical voltage, critical angular speed, critical temperature, and natural frequency of the structure. Another significant result is that, by increasing the lumped mass and coefficient of the spring in the first frequency of the cantilever cylindrical shell, increase or decrease of the natural frequency depends on the nonlinear temperature change parameter. The results of the current study are useful suggestions for designing electromechanical systems such as hydraulic pipes with the installation of the sensors to them.

Pressure Study on Pipe Transportation Associated with Cemented Coal Gangue Fly-Ash Backfill Slurry

Cemented coal gangue-fly ash backfill (CGFB) slurry has commonly been used to control subsidence damage caused by underground coal mining. This paper discusses the characteristics of CGFB slurry fluidity in its pipe transportation. A general description about the components of the CGFB is provided involving the percentage of composition, particle size distribution (PSD) and rheological performance. The CGFB flow characteristics of the slurry pipeline were simulated in a straight pipe and 90° elbow pipe, respectively, combined with the pressure loss and conveying velocity distribution. With the help of the commercial computational fluid dynamic (CFD) code FLUENT, the modeling was conducted with various slurry feeding velocities. These results showed the local resistance loss in a bending pipe is significantly higher than the resistance in a straight pipe under the same conditions associated with CGFB transportation. The velocity distribution of the slurry solid particles in the slurry’s movement forward is more decentralized as the hydraulic inlet velocity increases. Based on these simulation data, a correlation was developed to predict the resistance loss of the CGFB slurry as a function of the hydraulic inlet velocity, pipe diameter and CGFB slurry rheological characteristics.

Study on key performance parameters of hydro-pneumatic tensioner for top tensioned riser

In this paper an improved mathematical model of a hydro-pneumatic tensioner (HPT) system for top tensioned riser (TTR) is derived by consideration of friction, mass of piston and piston rod, tension loss in hydraulic oil piping, and compressibility of hydraulic oil. The vertical motion of the riser string is also considered. Subsequently, the proposed detailed model and the conventional simplified model are comparatively studied. Finally, the tension characteristic and performance parameters of the HPT are analyzed based on the proposed model. Results show that the conventional simplified model indeed overestimates the tension of tensioner as it neglects some performance parameters resulting in tension loss. The diameters of piston and piston rod and the initial pressure of high pressure (HP) gas have the most significant influence on the tension of the tensioner. The initial volume of HP gas and the initial pressure of low pressure (LP) gas also have some impact. The influence of the initial volume of LP gas and the inner diameter and length of the piping is relatively small. The research has some reference value for HPT and TTR design.

Fluid-Structure-Interaction Analysis of an Aero Hydraulic Pipe Considering Friction Coupling

A hydraulic pipe is a basic component of the aero hydraulic system, while high pressure and high speed lead to the enhancement of multiple field coupling effects, such as the structure, fluid, heat, and sound of the aero hydraulic pipe. A larger elastic deformation of the pipe and the more common unsteady flow of fluid can aggravate the vibration and noise of the hydraulic pipe system. Based on the 14-equation model of fluid-structure-interaction (FSI) vibration of aero hydraulic pipe, a model suitable for a wide Reynolds number range is proposed by comparing and analyzing various kinds of friction coupling models. This model is used for the FSI dynamic behavior analysis of aero hydraulic pipes, which improves the accuracy of FSI frequency-domain solutions under high Reynolds number conditions. Second, based on the 14-equation model of FSI vibration of aero hydraulic pipe and the transfer matrix method, the mathematical model of airframe deformation load of an aero hydraulic pipe is established, and the evolution law of the FSI dynamic behavior of the aero hydraulic pipe under different airframe deformation loads is analyzed. All the above analysis results were verified by the experimental analysis. The error of the analysis results of the FSI vibration frequency is smaller than 5% compared with the experimental results. The results show that the proposed method is feasible and effective for predicting the hydrodynamic behavior of the aero hydraulic pipes under load conditions.

Method for Hydraulic Calculation Warehouse Piping for Military Fuel Depots

Method for Hydraulic Calculation Warehouse Piping for Military Fuel Depots

Vibration analysis of a longitudinal polarized piezoelectric tubular energy harvester

In this contribution, theoretical model of the induced vibration and energy harvesting performances of a piezoelectric tubular energy harvester is established and analyzed. Analytical solutions to the model are obtained with the help of a system of linear operator equations. A series of simulations are done to investigate the influences of mechanical and electrical load parameters upon output performances of the energy harvester. Analyses of the characteristic roots show possible way to simplify the problem with asymptotic method. Results for state variables in the piezoelectric tube show good linear dependence of elastic displacements upon radial coordinates. Simulations on output performances indicate that the external connected electrical circuits should be compatible with the intended working conditions of the piezoelectric tubular energy harvester. The model developed here is expect to be useful in the design for self-powered sensor networks in hydraulic piping systems.

Multi-parameter dynamical measuring system using fibre Bragg grating sensors for industrial hydraulic piping

Due to the risk of failure induced by vibration fatigue, performance testing and condition monitoring are important to hydraulic piping systems in some critical industries such as nuclear power, oil and gas, and aerospace. A multi-parameter dynamical measuring system using Fibre Bragg Grating (FBG) sensors is proposed to detect multiple physical parameters (strain, temperature, pressure, acceleration, etc.) in industrial hydraulic piping. This paper investigates the multi-parameter measuring principle of FBG and presents the framework of the proposed system. Multi-parameter dynamical measuring experiments on a hydraulic piping test platform were carried out to validate the system. Multiple parameters of the hydraulic piping were obtained and analysed in the time, frequency and modal domains. The results obtained by FBG sensors are in good agreement with those detected by the reference electrical and piezoelectric sensors. The proposed system was implemented to monitor the clamping looseness of the pipe. Experimental results indicate that the proposed system could be used for multi-parameter dynamical measurements and real-time condition monitoring of complex industrial hydraulic piping systems in harsh environments.

Qualitative analysis of the failure risk of water pipes in terms of water supply safety

Abstract The work detailed here has sought to analyse the effects of emergency states on water-supply pipelines. For this purpose, a model hydraulic pipe network was created in Epanet 2, on the basis of actual operational data. Using the model, pipeline failures were simulated, and their effects described. The research methodology entails the simulated closure (i.e. failure) of individual pipes in the supply network, as followed by comparative analysis of the distribution of pressure across that network, in failure-free conditions and during a failure. The effects of failure in individual sections could thus be determined, in relation to the area with pressure lowered below the required value, the duration of that pressure reduction, and the potential number of recipients affected by limitation of water supply. The areas most exposed to pressure fluctuations in the water supply as a consequence of pipe-failure are thus pinpointed, with simulation results also serving in in the calculation of indicators for the risk of failure.

Finite element analysis of conical teeth for hydraulic pipe tongs

During well operation, corrosive gas such as H2S in the well will cause serious corrosion damage to the column. In order to minimize the impact of corrosion, the oilfield gradually replaced the standard steel casing by a corrosion-resistant alloy (CRA) casing. Conventional tongs was widely used on casing for mark-up and break-out operation. But Zhou et al [1] thought that the tong teeth destroys the galvanized layer of CRA on the casing surface, where the corrosion easily happens. Therefore, a design scheme of the conical teeth for hydraulic pipe tongs was proposed, and the mechanical properties of the conical teeth were simulated by finite element software to analyze the degree of damage to the casing.

Submarine and intertidal groundwater discharge through a complex multi-level karst conduit aquifer

The quantification of submarine and intertidal groundwater discharge (SiGD) or purely submarine groundwater discharge (SGD) from coastal karst aquifers presents a major challenge, as neither is directly measurable. In addition, the expected heterogeneity and intrinsic structure of such karst aquifers must be considered when quantifying SGD or SiGD. This study applies a set of methods for the coastal karst aquifer of Bell Harbour in western Ireland, using long-term onshore and offshore time series from a high-resolution monitoring network, to link catchment groundwater flow dynamics to groundwater discharge as SiGD. The SiGD is estimated using the “pollution flushing model”, i.e. a mass-balance approach, while catchment dynamics are quantified using borehole hydrograph analysis, single-borehole dilution tests, a water balance calculation, and cross-correlation analysis. The results of these analyses are then synthesised, describing a multi-level conduit-dominated coastal aquifer with a highly fluctuating overflow regime draining as SiGD, which is in part highly correlated with the overall piezometric level in the aquifer. This concept was simulated using a hydraulic pipe network model built in InfoWorks ICM [Integrated Catchment Modeling]® version 7.0 software (Innovyze). The model is capable of representing the overall highly variable discharge dynamics, predicting SiGD from the catchment to range from almost 0 to 4.3 m3/s. The study emphasises the need for long-term monitoring as the basis for any discharge studies of coastal karst aquifers. It further highlights the fact that multiple discharge locations may drain the aquifer, and therefore must be taken into consideration in the assessment of coastal karst aquifers.

Design for Additive Manufacturing: Optimization of Piping Network in Compact System With Enhanced Path-Finding Approach

This research aims at unleashing the potential of additive manufacturing technology in industrial design that can produce structures/devices with irregular component geometries to reduce sizes/weights. We explore, by means of path-finding, the length minimization of freeform hydraulic piping network in compact space under given constraints. Previous studies on path-finding have mainly focused on enhancing computational efficiency due to the need to produce rapid results in such as navigation and video-game applications. In this research, we develop a new Focal Any-Angle A* approach that combines the merits of grid-based method and visibility graph-based method. Specifically, we formulate pruned visibility graphs preserving only the useful portion of the vertices and then find the optimal path based on the candidate vertices using A*. The reduced visibility graphs enable us to outperform approximations and maintain the optimality of exact algorithms in a more efficient manner. The algorithm proposed is compared to the traditional A* on Grids, Theta* and A* on visibility graphs in terms of path length, number of nodes evaluated, as well as computational time. As demonstrated and validated through case studies, the proposed method is capable of finding the shortest path with tractable computational cost, which provides a viable design tool for the additive manufacturing of piping network systems.

Optimising Microbial Fuel Cell Treatment of Wastewater through Electrode Configuration

The cleaning and treatment of wastewater is a necessary, yet energy intensive practice. One of the greatest challenges society faces is therefore how to reduce the energy consumed in this process. A promising pathway to tackle this problem is by using innovative, low or zero energy consuming, technologies such as microbial fuel cells (MFCs), which harness the natural metabolism of bacteria and generate power. These microorganisms breakdown the organic content in wastewater i.e. treat/clean the liquid, and release electrons as part of their anaerobic respiration. Previous studies using MFC technology have been able to reduce the COD of the influent by up to 95% (1). Although MFCs do not generate large amounts of power, by incorporating them into existing treatment systems, the amount of energy needed to further clean wastewater is reduced. In addition, they continuously produce electricity, which can be fed back into the system and used to run low power devices (e.g. pumps for wastewater circulation). The configuration of MFCs greatly affects their performance, with the structure and materials that they are made out of being the governing factors for energy production, catholyte synthesis and wastewater treatment. In response to the need for optimum configuration, this study explores whether the positioning of the anode and cathode (either internally or externally on a cylindrical MFC) has a significant effect on the overall performance of an MFC. Two identical MFCs were tested, with the only variable being the anode and cathode configuration (internal anode with external cathode, and vice versa). The dimensions of the outer electrode were 40mm x 90mm, and 50mm x 70mm for the inner electrode, giving similar surface areas of 36cm2 and 35cm2, respectively. Results have so far shown that MFCs with the anode inside the cylinder and the cathode outside produce power outputs which are three times greater than those with internal cathodes and external anodes, with peak power outputs of 655µW and 219µW respectively. Practically, the benefits of having an internal anode include the advantage of using the MFC directly as part of the hydraulic (pipe) network, with the substrate fed through directly. This kind of design reduces the amount of external plumbing that is needed throughout the structure, and therefore reduces the risk of leakage. In addition, the external cathode can be partially covered or contained, which allows the half-cell to remain hydrated, and for any excess liquid (catholyte) to be easily collected. This is highly desirable due to the disinfectant properties of this liquid (2), which once again can be fed back into a wastewater treatment system and reduce overall energy demand. The acquisition of this knowledge is essential as MFCs need to be designed to suit target environments and applications, for both industrial and societal means. It is anticipated that the findings of this study will provide the MFC community with a decisive answer to how best design a cylindrical cell, which can be used as benchmark for future research.

An analysis of the dynamics of changes to water levels in the open piezometers of the Pieczyska dam in the study period between January 2016 and April 2017

The construction This paper aims to analyze the changes in trends of water levels in open piezometers installed at the dam in Pieczyska, which is the only seepage dam in Poland constructed via the silting technique. The scope of the research includes the analysis of piezometric data for each of the 82 active piezometers installed on the dam from January 2016 to April 2017 and taking into consideration the accident which occurred in February 2016, during which at the downstream of the dam there was hydraulic piping, following which ca. 150 m3of soil was eroded. A Statistical Rosner’s test for identifying and rejecting outliers was performed before carrying out the analysis of the piezometric data. A hypothesis was formulated that change in the trend occurred after the accident in February 2016. Using the method of least squares, for each open piezometer, two trend lines were matched to its water levels - the first one for the period January 2016-February 2016 and the second one for the period March 2016-April 2017. In this way, two slope coefficients for the linear function were obtained, together with the estimation of their errors. These slopes were compared using a statistical parallelism test.

Investigation of hydraulic fitting losses

Fluid flow in hydraulic systems, fittings, and piping causes hydraulic losses due to the change of flow direction and friction in the fluid. The main consequence of the resulting losses is the increase in the overall pressure gradient of the circuit. The paper is focused on the investigation of valve losses and the determination of resistance coefficients, the definition of which depends on the valve type. Methods of determination are of two types, i.e. experimental methods and mathematical methods. In the case of experimental methods, the procedures prescribed by the standards and regulations must be respected. Mathematical methods are related to defining an appropriate mathematical model and numerical approach. Both methods are applied to the ball valve and model verification is performed at the same time. The output of the thesis is the methodology for determination of resistance coefficients of valves with other diameters and other flowing media based on verified mathematical modeling.

Influence of Support Stiffness on Dynamic Characteristics of the Hydraulic Pipe Subjected to Basic Vibration

The basic vibration generated during the tunneling process of hard rock tunnel results in the change of the support stiffness of the hydraulic pipe, which causes the problem of reduction of pipe transmission efficiency. A transverse motion equation of the hydraulic pipe was established by correlating with Hamilton’s principle under basic vibration. In consideration of the fluid‐structure interaction (FSI), the support was simplified as an equivalent and a spring. The bidirectional fluid‐solid coupling analysis method was used to investigate dynamic characteristics of the pipeline under different support stiffness conditions. The finite element method (FEM) and the experimental analysis are applied to verify the proposed methodology. The numerical results show that the maximum displacement of the pipe decreases with the increase of the support stiffness; the maximum stress of the pipe decreases first and then increases with the increase of the support stiffness; the amplitude of the fluid pressure fluctuation at the outlet of the pipe increases with the increase of the support stiffness. But the fluid pressure fluctuation with the higher stiffness is first stable, which can indicate that the support stiffness can increase the damping of the pipe system. This study can get a significant access to the structural design of the pipeline under basic vibration.

Dynamic modeling, adaptive control and energy performance simulation of a hybrid hydronic space heating system

A dynamic model of a hybrid hydronic heating system has been developed. The overall model consists of a boiler, a heat exchanger, a ground loop heat pump, a ground loop heat exchanger, baseboard heaters (convector–radiators), and radiant floor hydraulic piping system. Two control strategies for improving the overall system performance were explored: (1) a conventional proportional-integral (PI) control and (2) an adaptive gain control. The simulation results showed that the performance of the adaptive controller is better than the fixed gain PI controller in disturbance rejection and stability. Energy simulations under three different operating strategies were conducted: (1) a fixed set-point PI control, (2) an outdoor air temperature reset control, and (3) an optimal set-point adaptive PI control. It was shown that the outdoor temperature reset strategy can save 4.5 and 19.9% energy under cold day and mild day conditions compared to the fixed set-point PI control strategy. The optimal adaptive PI control strategy resulted in higher energy savings of 6.6 and 22% as compared to the PI control under cold and mild day conditions, respectively. Practical application: Energy efficiency and sustainability are a major issue of importance in the design and operation of space heating systems. The proposed hybrid system combines a ground-source heat pump and a hot water boiler for space heating of both residential and commercial building applications. The heating system consists of radiant floor piping for the residential zones and hot water baseboard heaters (convector–radiators) for the commercial zones. An energy optimal adaptive control strategy is designed to improve energy efficiency and temperature control performance of the hybrid system. The control strategy is simple and can be implemented on the existing building control systems.

Reduced-Parameter Method for Maximum Entropy Analysis of Hydraulic Pipe Flow Networks

AbstractA maximum entropy (MaxEnt) method is developed to predict flow rates or pressure gradients in hydraulic pipe networks without sufficient information to give a closed-form (deterministic) so...

Practical evaluation of inorganic contaminant presence in a drinking water distribution system after hydraulic disturbance

The accumulation of loose deposits in a drinking water distribution system (DWDS) is a potential risk for water quality. In this work, hydraulic disturbance was simulated in different areas of a large DWDS. The water quality features before and after the disturbance were compared, and the solid deposits captured from different experimental sites were characterized. The results showed that the hydraulic disturbance increased the water turbidity and color, which can be attributed to the re-suspension of iron and manganese oxide particulates. The concentrations of arsenic and lead increased after the disturbance, and a significant positive correlation was observed between the iron and arsenic concentrations. The solid deposits exhibited distinct characteristics in different sites based on the normal hydraulic conditions and pipe material. The main crystalline iron substances were goethite and pyrosiderite. The iron and arsenic contents in the deposits had a positive correlation with their concentrations in the disturbed water. The combination status of manganese, chromium, and lead in the deposits was different from that of arsenic.