Effect of Stator Geometry on the Performance of a Positive Displacement Hydraulic Turbine

2019 ◽  
Author(s):  
Arihant Sonawat ◽  
Jin-Hyuk Kim ◽  
Seung-Jun Kim ◽  
Young-Seok Choi ◽  
Hyeon-Mo Yang ◽  
...  
Keyword(s):  
Control Valve ◽  
Hydraulic Turbine ◽  
Primary Objective ◽  
Low Flow ◽  
Working Fluid ◽  
Pipeline System ◽  
Positive Displacement ◽  
Ansys Cfx ◽  
Differential Control ◽  
Water Supply Pipeline

Abstract Positive displacement turbine (PDT) is a special class of hydraulic turbine which finds its usage in the applications involving very low flow rates with high heads and very low specific speeds. In the present case, a PDT was designed and developed to replace the pressure differential control valve (PDCV) and to harness the unused differential pressure energy from the water supply pipeline system. The turbine was designed considering the on-site available head and flowrate. The rotors were twisted to damp the fluctuations in pressure, flow rate and torque. The primary objective of the present study was to analyze the effect of the stator shape on the performance of PDT using Computational Fluid Dynamics approach. The governing equations of the fluid flow were solved using an unsteady approach to capture accurately the pulsating nature of the flow using ANSYS CFX v17.1. Initially a circular stator turbine was used for transporting the working fluid to and from the turbine rotors and later the effects of square and rectangular shaped stator designs were also checked. It was observed that the performance of the PDT slightly improved with rectangular and square stators in terms of hydraulic efficiency than with circular stator with low flow fluctuations.

scholarly journals Characterization of Limacon Gas Expanders With Consideration to the Dynamics of Apex Seals and Inlet Control Valve

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Truong H. Phung ◽  
Ibrahim A. Sultan
Keyword(s):  
Fluid Velocity ◽  
Control Valve ◽  
Working Fluid ◽  
Inlet Valve ◽  
Positive Displacement ◽  
Working Volume ◽  
Thermodynamic Performance ◽  
Circular Curves

Limaçon machine, of which the relative motion between the rotor and housing follows the limaçon curve, belongs to a class of rotary positive displacement machines. The profiles of rotors and housings of those machines can be constructed of either limaçon or circular curves, hence the names: limaçon-to-limaçon, circolimaçon, and limaçon-to-circular machines. This paper presents the investigation into the thermodynamic performance of the limaçon-to-circular machines with the presence of apex seals and inlet valve. This paper sets out by briefly introducing the limaçon technology and the construction of the limaçon-to-circular machine working volume. The mathematical descriptions of ports' positions and areas have also been introduced. The paper then discusses the flow and phase composition of working fluid through the working chambers as well as how the fluid velocity is modeled and calculated. Then the seal dynamic model and response of inlet valve are presented followed by the machine thermodynamic model. A case study has also been presented to show the responses of seals and inlet valve during the machine operation.

Positive displacement turbine - A novel solution to the pressure differential control valve failure problem and energy utilization

Energy ◽  
2020 ◽  
Vol 190 ◽  
pp. 116400 ◽  
Author(s):  
Arihant Sonawat ◽  
Seung-Jun Kim ◽  
Hyeon-Mo Yang ◽  
Young-Seok Choi ◽  
Kyung-Min Kim ◽  
...  
Keyword(s):  
Control Valve ◽  
Pressure Differential ◽  
Energy Utilization ◽  
Positive Displacement ◽  
Differential Control

Seismic Damage Assessment of Urban Water Supply Pipeline

2013 ◽  
Vol 316-317 ◽  
pp. 723-726
Author(s):  
Jian Qun Jiang ◽  
Xiao Wen Yao ◽  
Yi Ting Lu
Keyword(s):  
Water Supply ◽  
Damage Assessment ◽  
Longitudinal Direction ◽  
Underground Water ◽  
Seismic Damage ◽  
Pipeline System ◽  
Seismic Damage Assessment ◽  
Water Pipeline ◽  
Ground Condition ◽  
Water Supply Pipeline

Water supply pipeline system is a key issue in urban lifeline engineering, and the seismic assessment for the system damage is of significant importance. In this study, method of seismic damage assessment on underground water supply pipeline is introduced. With emphasis on the uncertainties of earthquake level, ground condition, soil-pipe interaction and capacity to resist pipe deformation in longitudinal direction, the check point method is applied to the reliability study of water pipeline, and a case study is presented to show the implementation of the proposed model.

A Remote Area Power Supply Using Wind Power and Cold Thermal Storage

2002 ◽  
Author(s):  
Kenneth C. Brown
Keyword(s):  
Energy Source ◽  
Power Supply ◽  
Rankine Cycle ◽  
Thermal Storage ◽  
Primary Objective ◽  
Remote Area ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Vapour Compression

A remote area power supply using cold thermal storage and wind as the energy source is proposed. The primary objective is to provide a renewable energy remote area power supply with cheaper and more robust storage than lead-acid batteries. The proposal amalgamates a vapour compression refrigeration system with a Rankine cycle engine, both using the same working fluid. A tank of freezing brine acts as the condenser in the Rankine cycle and as the evaporator in the refrigeration cycle but also provides the “energy storage”. Analysis of the system indicates that it is practical and that its performance is comparable with existing battery based systems.

scholarly journals CFD Analysis of the Optimization of Length of Capillary Tube for a Vapor Compression Refrigeration System

2021 ◽  
Vol 9 (8) ◽  
pp. 2567-2578
Author(s):  
Ms. K. P. Bhangle
Keyword(s):  
Capillary Tube ◽  
Flow Analysis ◽  
Small Diameter ◽  
Flow Characteristics ◽  
Working Fluid ◽  
Vapor Compression ◽  
Adiabatic Flow ◽  
Ansys Cfx ◽  
Vapor Compression Refrigeration ◽  
R 134A

Abstract: The capillary tube is commonly employed in refrigerant flow control systems. As a result, the capillary tube's performance is optimal for good refrigerant flow. Many scholars concluded performance utilising experimental, theoretical, and analysis-based methods. This paper examines the flow analysis of a refrigerant within a capillary tube under adiabatic flow circumstances. For a given mass flow rate, the suggested model can predict flow characteristics in adiabatic capillary tubes. In the current work, R-134a refrigerant has been replaced by R600a refrigerant as a working fluid inside the capillary tube, and the capillary tube design has been modified by altering length and diameter, which were obtained from reputable literature. The analysis is carried out using the ANSYS CFX 16.2 software. The results show thatutilising a small diameter and a long length (R600a refrigerant flow) is superior to the present helical capillary tube. The most appropriate helical coiled design with a diameter of 0.8 mm and a length of 3 m is proposed. Keywords: Capillary Tube, Condenser, Refrigeration effect, CFD.

Radial Impeller Forces Using CFD: Part II — A Comparison Between Compressible and Incompressible Flows

2002 ◽  
Author(s):  
Daniel O. Baun ◽  
Ronald D. Flack
Keyword(s):  
Mach Number ◽  
Flow Rate ◽  
Incompressible Flows ◽  
Lateral Force ◽  
Magnetic Bearing ◽  
Flow Coefficient ◽  
Low Flow ◽  
Working Fluid ◽  
Centrifugal Impeller ◽  
Cfd Model

Lateral centrifugal impeller forces are calculated using the CFD model developed in Part I of this paper. The impeller forces are evaluated by integrating the pressure and momentum profiles at both the impeller inlet and exit planes. Direct impeller lateral force measurements were made using a magnetic bearing supported pump rotor. Comparisons between the simulated and measured forces are first made for both average and transient impeller forces with water as the working fluid. Air was then substituted as the working fluid in the validated CFD model and the effect of impeller Mach number and Reynolds number on the static impeller lateral forces was investigated. The non-dimensional lateral impeller force characteristics as a function of normalized flow coefficient are similar in character between the incompressible and compressible case. At the matching point flow coefficient the non-dimensional impeller force magnitude was the same for all compressible and incompressible simulations. For any normalized flow rate other than the matching point flow rate, the magnitude of the non-dimensional impeller force increased as the Mach number increased. As the choke condition was approached the magnitude of the impeller force increased exponentially. As the Mach number increased the transition of the force orientation vector from the low flow asymptote to the high flow asymptote occurred over a progressively smaller range of flows.

Optimal sensor placement to detect ruptures in pipeline systems subject to uncertainty using an Adam-mutated genetic algorithm

2021 ◽  
pp. 147592172110565
Author(s):  
Chungeon Kim ◽  
Hyunseok Oh ◽  
Byung Chang Jung ◽  
Seok Jun Moon
Keyword(s):  
Genetic Algorithm ◽  
Simulation Model ◽  
Sensor Network ◽  
Sensor Placement ◽  
Mixed Integer ◽  
Working Fluid ◽  
Small Scale ◽  
Pipeline System ◽  
Optimal Sensor Placement ◽  
Pipeline Network

Pipelines in critical engineered facilities, such as petrochemical and power plants, conduct important roles of fire extinguishing, cooling, and related essential tasks. Therefore, failure of a pipeline system can cause catastrophic disaster, which may include economic loss or even human casualty. Optimal sensor placement is required to detect and assess damage so that the optimal amount of resources is deployed and damage is minimized. This paper presents a novel methodology to determine the optimal location of sensors in a pipeline network for real-time monitoring. First, a lumped model of a small-scale pipeline network is built to simulate the behavior of working fluid. By propagating the inherent variability of hydraulic parameters in the simulation model, uncertainty in the behavior of the working fluid is evaluated. Sensor measurement error is also incorporated. Second, predefined damage scenarios are implemented in the simulation model and estimated through a damage classification algorithm using acquired data from the sensor network. Third, probabilistic detectability is measured as a performance metric of the sensor network. Finally, a detectability-based optimization problem is formulated as a mixed integer non-linear programming problem. An Adam-mutated genetic algorithm (AMGA) is proposed to solve the problem. The Adam-optimizer is incorporated as a mutation operator of the genetic algorithm to increase the capacity of the algorithm to escape from the local minimum. The performance of the AMGA is compared with that of the standard genetic algorithm. A case study using a pipeline system is presented to evaluate the performance of the proposed sensor network design methodology.

Numerical Anaysis of a Thermopneumatic Micropump

2010 ◽  
Author(s):  
S. Shahsavari ◽  
M. B. Shafii ◽  
M. H. Saidi
Keyword(s):  
Fluid Flow ◽  
Numerical Study ◽  
Three Dimensional ◽  
Working Fluid ◽  
Structure Interaction ◽  
Positive Displacement ◽  
Dimensional Simulation ◽  
Center Deflection ◽  
Bidirectional Flow ◽  
Secondary Fluid

Thermopneumatic micropump is one type of positive displacement micropump, which has many applications due to its relatively large stroke volume, low working voltage, and simple fabrication in microscale. In this paper, a numerical study of heat transfer and fluid flow in a valveless thermopneumatically driven micropump is presented. For rectifying the bidirectional flow, a nozzle and a diffuser are used as the inlet and outlet channels of the chamber. Since the fluid flow is induced by the motion of a diaphragm, the numerical simulation includes fluid structure interaction, which requires applying a dynamic mesh. The domain of solution is divided into two sections; the actuator unit, which contains the secondary fluid, and the main chamber through which the working fluid is passing. The temperature distribution, the pressure variations, and the center deflection of the diaphragm are obtained. In order to validate the model, the numerical results are compared with some experimental data, which shows fair consistency. According to the results of the three dimensional simulation, the rectification efficiency for the nozzle and diffuser channels depends on the frequency.

Modelling and Reducing Fuel Flow Pulsation of a Fuel-Metering System by Improving Response of the Pressure Control Valve During Pump Mode Switching in a Turbofan Engine

2019 ◽  
Author(s):  
Seiei Masuda ◽  
Fumio Shimizu ◽  
Masaki Fuchiwaki ◽  
Kazuhiro Tanaka
Keyword(s):  
Control Valve ◽  
Flow Region ◽  
Pressure Control ◽  
Low Flow ◽  
Mode Switching ◽  
Pump Mode ◽  
Turbofan Engine ◽  
Fuel Pump ◽  
Fuel Flow ◽  
Pressure Control Valve

Abstract In an aircraft turbofan engine, a fuel metering unit meters and supplies the required fuel to the engine according to the flight situation. When a centrifugal fuel pump (CFP) is used as the fuel pump, the ratio of hydraulic power per weight can be increased by raising the rated rotational speed, so the weight of the fuel pump can be decreased compared to when using a gear pump (GFP). There is an advantage that it can be reduced significantly. However, since the operating range of the fuel pump is wide, it is not effective to use CFP in an extremely low flow rate region because the fuel temperature rises due to its PQ characteristics and a large loss. Therefore, it is considered effective to combine CFP and GFP as pressure sources, and to use GFP in the low flow region and CFP in the high flow region. For that purpose, it is necessary to have a pump mode switching mechanism. The disadvantage in this case is that changing the pump mode causes a large pressure change of the fuel pressure source, which in turn causes fuel flow pulsations. There are three possible ways to solve this problem. The first method is to keep the differential pressure control valve (DPCV) unit response constant, which keeps the metering valve differential pressure constant in FMS. A second method is to remove high frequency components that the DPCV cannot follow pressure changes in the fuel control system. A third method is to keep the pressure difference between the two fuel sources small and to reduce the amplitude of the applied disturbance. In this paper, the first method, which makes DPCV response high response, is verified by modeling and simulation, and its effectiveness is confirmed.

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