Extending the Global-Gradient Algorithm to Solve Pressure-Control Valves

2020 ◽  
Vol 146 (8) ◽  
pp. 04020055
Author(s):  
Gioia Foglianti ◽  
Stefano Alvisi ◽  
Marco Franchini ◽  
Ezio Todini
Keyword(s):  
Pressure Control ◽  
Gradient Algorithm ◽  
Control Valves ◽  
Global Gradient Algorithm

scholarly journals Testing linear solvers for global gradient algorithm

2014 ◽  
Vol 16 (5) ◽  
pp. 1178-1193 ◽  
Author(s):  
Orazio Giustolisi ◽  
Naser Moosavian
Keyword(s):  
Linear System ◽  
Water Distribution ◽  
Direct Method ◽  
Mathematical Problem ◽  
Network Models ◽  
Water Distribution Network ◽  
Mass Conservation ◽  
Gradient Algorithm ◽  
Global Gradient Algorithm ◽  
Pressure Driven

Steady-state Water Distribution Network models compute pipe flows and nodal heads for assumed nodal demands, pipe hydraulic resistances, etc. The nonlinear mathematical problem is based on energy and mass conservation laws which is solved by using global linearization techniques, such as global gradient algorithm (GGA). The matrix of coefficients of the linear system inside GGA belongs to the class of sparse, symmetric and positive definite. Therefore a fast solver for the linear system is important in order to achieve the computational efficiency, especially when multiple runs are required. This work aims at testing three main strategies for the solution of linear systems inside GGA. The tests are performed on eight real networks by sampling nodal demands, considering the pressure-driven and demand-driven modelling to evaluate the robustness of solvers. The results show that there exists a robust specialized direct method which is superior to all the other alternatives. Furthermore, it is found that the number of times the linear system is solved inside the GGA does not depend on the specific solver, if a small regularization to the linear problem is applied, and that pressure-driven modelling requires a greater number which depends on the size and topology of the network and not only on the level of pressure deficiency.

scholarly journals DYNAMIC CHARACTERISTICS OF OIL HYDRAULIC PRESSURE CONTROL VALVES

1975 ◽  
Vol 18 (122) ◽  
pp. 858-865 ◽  
Author(s):  
Hirohisa TANAKA ◽  
Tomo-o ISHIHARA ◽  
Eiichi KOJIMA
Keyword(s):  
Dynamic Characteristics ◽  
Pressure Control ◽  
Hydraulic Pressure ◽  
Control Valves

Guide for Selecting Pressure Control Valves With Actuators Used in Pipeline Applications

2010 ◽  
Author(s):  
Jack Broyles ◽  
Roger Shirt
Keyword(s):  
Selection Criteria ◽  
Large Diameter ◽  
Control Valve ◽  
Pressure Control ◽  
Industrial Applications ◽  
Performance Criteria ◽  
Effective Control ◽  
Critical Threshold ◽  
Control Valves ◽  
Selection Strategies

This paper will discuss guidelines for the selection of pressure control valves (PCV) with electro-hydraulic actuators for use in liquid petroleum pipelines. The performance criteria for PCVs functioning in pipeline pressure control applications are distinct from those used in other industrial applications. Also, PCVs required for large diameter petroleum pipeline represent a relatively small number of total control valve applications. For these reasons, general practitioners of control valve selections, typically engineers at EPCs, commonly apply selection strategies that are effective in other industrial applications, but tend to be less so in pipeline applications. This paper will discuss control valve selection criteria including Critical Threshold Capacity, Effective Control Region and Valve Gain Band. Actuator selection criteria discussed in this paper includes Torque Requirements, Speed of Response, and Positioning Resolution.

scholarly journals A Review of Capillary Pressure Control Valves in Microfluidics

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 405
Author(s):  
Shaoxi Wang ◽  
Xiafeng Zhang ◽  
Cong Ma ◽  
Sheng Yan ◽  
David Inglis ◽  
...  
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Capillary Pressure ◽  
Open Channel ◽  
Control Valve ◽  
Pressure Control ◽  
Pressure Effects ◽  
Helpful Tool ◽  
Control Valves ◽  
Pressure Control Valve

Microfluidics offer microenvironments for reagent delivery, handling, mixing, reaction, and detection, but often demand the affiliated equipment for liquid control for these functions. As a helpful tool, the capillary pressure control valve (CPCV) has become popular to avoid using affiliated equipment. Liquid can be handled in a controlled manner by using the bubble pressure effects. In this paper, we analyze and categorize the CPCVs via three determining parameters: surface tension, contact angle, and microchannel shape. Finally, a few application scenarios and impacts of CPCV are listed, which includes how CPVC simplify automation of microfluidic networks, work with other driving modes; make extensive use of microfluidics by open channel, and sampling and delivery with controlled manners. The authors hope this review will help the development and use of the CPCV in microfluidic fields in both research and industry.

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