scholarly journals Sensitivity Analysis of Hydraulic Transient Simulations Based on the MOC in the Gravity Flow

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3464
Author(s):  
Jinhao Liu ◽  
Jianhua Wu ◽  
Yusheng Zhang ◽  
Xinhao Wu
Keyword(s):  
Sensitivity Analysis ◽  
Friction Factor ◽  
Flow Rate ◽  
Parameter Sensitivity ◽  
Gravity Flow ◽  
Pipe Diameter ◽  
Maximum Pressure ◽  
Closing Time ◽  
Hydraulic Transient ◽  
Transient Simulations

The purpose of this study was to evaluate the sensitivity of input parameters to output results when using the method of characteristics (MOC) for hydraulic transient simulations. Based on a gravity flow water delivery project, we selected six main parameters that affect the hydraulic transient simulation and selected maximum pressure as the output parameter in order to perform a parameter sensitivity analysis. The Morris sensitivity analysis (Morris) and the partial rank correlation coefficient method based on Latin hypercube sampling (LHS-PRCC) were both adopted. The results show that the sensitivity of each parameter is the same except for the friction factor. The flow rate and Young’s modulus are positively correlated with the maximum pressure, whereas the pipe diameter, valve closing time, and wall thickness are negatively correlated. It is discussed that the variability of the friction factor comes from the function of the flow and pressure regulating valve. When other conditions of the gravity flow project remain unchanged, the maximum pressure increases with the increase in the friction factor. The flow rate, pipe diameter, and valve closing time are the key parameters that affect the model. Meanwhile, Morris and LHS-PRCC proved to be effective methods for evaluating parameter sensitivity in hydraulic transient simulations.

Friction Factors of Oilfield Water Injection Network - Research on Solving Approach

2013 ◽  
Vol 765-767 ◽  
pp. 920-923
Author(s):  
Song Wang ◽  
Dong Ma ◽  
Zhong Chen Yu ◽  
Xue Jiao Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Boundary Conditions ◽  
Experimental Method ◽  
Friction Factor ◽  
Flow Rate ◽  
Water Injection ◽  
Optimal Result ◽  
Pipe Section ◽  
Friction Factors ◽  
Oilfield Water

Oilfield water injection network is a special network, where all pressure and flow rate of node is known. Using empirical friction factor value formerly leads to great deviation between optimal result of network and fact operating condition, because of small pipe diameter, severe scale and lots of valves, which is difficult to guide Oilfield production. Firstly, possible pipe combination, that needs to give friction factor value, is found by orthogonal experimental method. Then friction factor sensitivity of pipe section is analyzed in the possible pipe combination by sensitivity analysis, supplementary boundary conditions is gotten, friction factor value of every pipe is given according to solving analogical node equation method.

scholarly journals Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): sensitivity analysis on the Newberry volcanic setting

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hannah R. Doran ◽  
Theo Renaud ◽  
Gioia Falcone ◽  
Lehua Pan ◽  
Patrick G. Verdin
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Energy Flow ◽  
Closed Loop ◽  
Working Fluid ◽  
Valuable Insight ◽  
Deep Borehole

AbstractAlternative (unconventional) deep geothermal designs are needed to provide a secure and efficient geothermal energy supply. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as the working fluid mass flow rate, the casing and cement thermal properties, and the wellbore radii dimensions. The results conclude the highest energy flow rate to be 1.5 MW, after an annulus radii increase and an imposed mass flow rate of 5 kg/s. At 3 kg/s, the DBHE yielded an energy flow rate a factor of 3.5 lower than the NWG 55-29 conventional design. Despite this loss, the sensitivity analysis allows an assessment of the key thermodynamics within the wellbore and provides a valuable insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of subcritical conditions, and could aid the development of unconventional designs within future EGS work like the Newberry Deep Drilling Project (NDDP). Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems to support EGS projects that could extend to deeper depths.

scholarly journals Impact of Orifice-to-Pipe Diameter Ratio on Leakage Flow: An Experimental Study

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2189
Author(s):  
Tingchao Yu ◽  
Xiangqiu Zhang ◽  
Iran E. Lima Neto ◽  
Tuqiao Zhang ◽  
Yu Shao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Pipe Wall ◽  
Pressure Head ◽  
Diameter Ratio ◽  
Pipe Diameter ◽  
Leakage Flow ◽  
Leakage Flow Rate ◽  
Different Shapes ◽  
Real Scale

The traditional orifice discharge formula used to estimate the flow rate through a leak opening at a pipe wall often produces inaccurate results. This paper reports an original experimental study in which the influence of orifice-to-pipe diameter ratio on leakage flow rate was investigated for several internal/external flow conditions and orifice holes with different shapes. The results revealed that orifice-to-pipe diameter ratio (or pipe wall curvature) indeed influenced the leakage flow, with the discharge coefficient ( C d ) presenting a wide variation (0.60–0.85). As the orifice-to-pipe diameter ratio decreased, the values of C d systematically decreased from about 12% to 3%. Overall, the values of C d also decreased with β (ratio of pressure head differential at the orifice to wall thickness), as observed in previous studies. On the other hand, orifice shape, main pipe flow velocity, and external medium (water or air) all had a secondary effect on C d . The results obtained in the present study not only demonstrated that orifice-to-pipe diameter ratio affects the outflow, but also that real scale pipes may exhibit a relevant deviation of C d from the classical range (0.61–0.67) reported in the literature.

scholarly journals Pneumatic transport of bulk materials in construction of composite floating docks

2021 ◽  
pp. 1-14
Author(s):  
A.S. Rashkovskyi ◽  
A.V. Shchedrolosiev ◽  
V.M. Neiman ◽  
O.Y. Kanash
Keyword(s):  
Wear Resistance ◽  
Transport System ◽  
Flow Rate ◽  
Pneumatic Transport ◽  
Pipe Diameter ◽  
Bulk Materials ◽  
Useful Life ◽  
Materials Used ◽  
Theoretical Results

Investigations of pneumatic transport of bulk materials used in shipbuilding have carried out. Their abrasiveness, wear of straight and curved sections of pipelines were investigated. Theoretically, the dependences of the amount of wear on various factors were defined: abrasiveness and concentration of transported particles, flow rate, pipe diameter and wear resistance of its material, structural and operational features of the transport system, etc. Formulas for determining the maximum useful life of straight and curved sections of pipelines are obtained. Theoretical results confirmed experimentally.

Parameter Sensitivity Analysis of a Large-Scale System With Several Components Interacting in Series

1989 ◽  
Author(s):  
H. Torab
Keyword(s):  
Sensitivity Analysis ◽  
Large Scale ◽  
Optimization Problems ◽  
Parameter Sensitivity ◽  
Engineering Optimization ◽  
Parameter Sensitivity Analysis ◽  
Large Scale Systems ◽  
In Series ◽  
Special Case ◽  
Engineering Optimization Problems

Abstract Parameter sensitivity for large-scale systems that include several components which interface in series is presented. Large-scale systems can be divided into components or sub-systems to avoid excessive calculations in determining their optimum design. Model Coordination Method of Decomposition (MCMD) is one of the most commonly used methods to solve large-scale engineering optimization problems. In the Model Coordination Method of Decomposition, the vector of coordinating variables can be partitioned into two sub-vectors for systems with several components interacting in series. The first sub-vector consists of those variables that are common among all or most of the elements. The other sub-vector consists of those variables that are common between only two components that are in series. This study focuses on a parameter sensitivity analysis for this special case using MCMD.

Simulation Analysis and Optimization of Lubricating Oil System

2021 ◽  
Author(s):  
Qiongxiao Wu ◽  
Jianjun Wang ◽  
Jingming Chen ◽  
Pengzheng Li
Keyword(s):  
Simulation Model ◽  
Simulation Analysis ◽  
Sudden Change ◽  
Pressure Change ◽  
Lubricating Oil ◽  
Maximum Pressure ◽  
Closing Time ◽  
Original Design ◽  
Relief Valve ◽  
Simulation Results

Abstract Based on the one-dimensional simulation model of lubricating oil system is established and analyzed by using FLOWMASTER software, this paper proposes a new method of optimizing lubricating oil system by PID technology. Ensure that the configuration requirements and control strategies of the relevant accessories of the simulation model are satisfied with the design requirements. Firstly, by simulating lubricating oil pressure fluctuation and lubricating oil flow distribution under Open/Close Valve in different opening and closing time, the optimal opening/closing time of Open/Close Valve is determined to be 0.2 s and 0.5 s respectively. Secondly, by writing the controller script file combined with a controller to realize automatic unloading relief valve simulation, determine the relief valve pressure regulating range of 0∼0.38 MPa, For precision of constant pressure valve of oil spill, the simulation results show that the average 10 m3/h flow caused by pressure changes of about 0.06 MPa. Under the flow sudden change signal of about 40 m3/h, the maximum pressure change is less than 0.1 MPa. Through the simulation results, it is found that most of the lubrication parts in the original design have the phenomenon of flow redundancy, which causes unnecessary pump power loss. The system is optimized by PID technology. By comparing the simulation results before and after optimization, it is found that the speed of constant displacement pump could be changed in time by PID controller, and the flow redundancy could be improved significantly, so the lubricating oil system could be lower consumption and achieve the purpose of optimization.

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