The Pumping Dynamics of a Positive Displacement Pump Employing Self-Acting Valves

1990 ◽  
Vol 112 (4) ◽  
pp. 748-754 ◽  
Author(s):  
K. A. Edge ◽  
P. N. Brett
Keyword(s):  
Pressure Fluctuations ◽  
Experimental Tests ◽  
General Purpose ◽  
Operating Conditions ◽  
Cylinder Pressure ◽  
Valve Timing ◽  
Inlet Valve ◽  
Positive Displacement ◽  
Displacement Pump ◽  
Valve Dynamics

The paper describes a general purpose digital computer model for the analysis of the pumping dynamics of positive displacement pumps employing self-acting valves. This model is verified by comparison with experimental tests on a diaphragm separator pump. Predicted and simulated cylinder pressure transients and inlet and delivery valve dynamics are compared over the complete pumping cycle. Close agreement between theory and experiment is achieved. The induction performance of the pump is examined in detail and the effects of operating conditions on volumetric efficiency are presented. The effect of inlet valve timing on delivery manifold pressure fluctuations is also discussed.

scholarly journals The Influence of Water and Mineral Oil on Volumetric Losses in the Displacement Pump for Offshore and Marine Applications

2019 ◽  
Vol 26 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Paweł Śliwiński
Keyword(s):  
Mathematical Model ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Mineral Oil ◽  
Water Pump ◽  
Positive Displacement ◽  
Oil Pump ◽  
Influence Of Water ◽  
Displacement Pump ◽  
Marine Applications

Abstract In this paper, volumetric losses in a positive displacement pump supplied with water and mineral oil are described and compared. The experimental tests were conducted using a prototype of a satellite pump (with a non-circular tooth working mechanism). In this paper, the sources of volumetric losses in this pump are characterized. On this basis, a mathematical model of these losses has been presented. The results of the calculation of volumetric losses according to the model are compared with the results of the experiment. Experimental studies have shown that the volumetric losses in the water pump are even 3.2 times greater than the volumetric losses in the oil pump. It has been demonstrated that the mathematical model describing the volumetric losses both in the water pump and in the oil pump is quite good. It has been found that the results from the loaded pump simulation (at ∆p=25MPa and ant n=1500rpm) differ from the results of the experiment by no more than 5% both for oil and water.

scholarly journals Experimental Performance of Solar Receivers Designed to Use Oil as a Heat Transfer Fluid

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
J. S. P. Mlatho
Keyword(s):  
Heat Transfer ◽  
Low Cost ◽  
Thermal Studies ◽  
Experimental Tests ◽  
Heat Transfer Fluid ◽  
Flow Meter ◽  
Positive Displacement ◽  
Displacement Pump ◽  
Parabolic Dish ◽  
Parabolic Dish Concentrator

A parabolic dish concentrator (PDC) has been designed to be used for charging a thermal energy storage (TES) that is for indirect cooking purpose. Three different receivers have been designed, fabricated, and their performance tested experimentally. The three designs are Volumetric Flask (VF), Volumetric Box (VB), and Conical Tube (CT) receivers. The receivers have been fabricated to use oil as a heat transfer fluid. Of the three designs, the CT receiver has the highest efficiency for a given flow rate, thus making it the best receiver. A positive displacement pump was also designed and constructed for the experimental tests. The pump is used to drive the oil through the receivers and also to act as a flow meter. Thus a low-cost and high-temperature positive displacement pump and a flow meter have been designed and fabricated for use in solar thermal studies.

scholarly journals The Influence of Water and Mineral Oil On Mechanical Losses in the Displacement Pump for Offshore and Marine Applications

2018 ◽  
Vol 25 (s1) ◽  
pp. 178-188 ◽  
Author(s):  
Paweł Śliwiński
Keyword(s):  
Mathematical Model ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Mineral Oil ◽  
Water Pump ◽  
Positive Displacement ◽  
Oil Pump ◽  
Influence Of Water ◽  
Displacement Pump ◽  
Marine Applications

Abstract In this paper mechanical losses in a positive displacement pump supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted by using a prototype satellite pump of a special design. The design of the satellite pump is presented in the article. The pump features and a non-circular tooth working mechanism was developed to work with both water and mineral oil. The sources of mechanical losses in such pump are also characterized in this paper. On this basis, a mathematical model of the losses has been developed and presented. The results of the calculation of mechanical losses according to the model are compared with the results of the experiment. The experimental studies have shown that the mechanical losses in the water pump are even 2.8 times greater than those in the oil pump. It has been demonstrated that the mathematical model well describes the mechanical losses both in the water pump and the oil pump. It has been found that the results from the loaded pump simulation (at Δp=25MPa) differ from the results of the experiment by no more than 5% both for oil and water.

Optimizing Pump Selection for Energy Efficiency Across Multiple Operating Conditions Using True Weighted Efficiency (TWE)

2019 ◽  
Author(s):  
Trygve Dahl
Keyword(s):  
Energy Efficiency ◽  
The United States ◽  
General Purpose ◽  
Operating Conditions ◽  
Pump Efficiency ◽  
The European Union ◽  
Optimization Program ◽  
Positive Displacement ◽  
New Energy ◽  
Control Curves

Abstract Energy efficiency is emphasized more actively across the pump industry. Legislation in the European Union and in the United States utilize new energy efficiency ranking metrics, but neither of these methods are conveniently applied to customer specified load conditions. True Weighted Efficiency, or TWE, is introduced as a general-purpose, universal pump efficiency metric for pumps operating under multiple operating conditions. The TWE is derived accurately from first principles, using generalized load profiles that include control curves, multiple discrete operating points based on those control curves, and the time of operation at each operating point. A pump selection/optimization program is used to numerically demonstrate the TWE method. Various examples are presented, contrasting candidate pumps based on three different optimization strategies. The study reveals that the pump with the best design point efficiency may not be the best choice from a TWE or an evaluated cost perspective. This method is applicable to rotodynamic or positive displacement pumps operating at fixed or variable speed, on/off operation, throttle control, or by-pass control. and other turbomachinery as well. The TWE methodology, when combined with a pump selection/optimization program, will help practitioners design systems that reduce energy consumption for new or reconfigured pump applications.

scholarly journals Hydraulic Vibration and Possible Exciting Sources Analysis in a Hydropower System

2021 ◽  
Vol 11 (12) ◽  
pp. 5529
Author(s):  
Aili Shen ◽  
Yimin Chen ◽  
Jianxu Zhou ◽  
Fei Yang ◽  
Hongliang Sun ◽  
...  
Keyword(s):  
Vibration Mode ◽  
Draft Tube ◽  
Pressure Fluctuations ◽  
Experimental Tests ◽  
Dominant Frequency ◽  
Rotational Frequency ◽  
Operating Conditions ◽  
Mode Shapes ◽  
Vortex Rope ◽  
Hydropower System

To understand the hydraulic vibration characteristics in a traditional hydropower system and identify possible exciting sources that may induce serious hydraulic vibrations in the flow passage, experimental tests and numerical calculations were conducted for different operating conditions. The experimental results show that the pressure fluctuations are mainly related to the vortex rope phenomena in the draft tube, and the dominant frequency of pressure fluctuation is 0.2~0.4 times the runner rotational frequency (fn). The numerical results show all the attenuating factors are negative, which indicates the system itself is stable on the condition that all the hydraulic elements have steady operating performance. The free vibration analyses confirm that the frequency range of the vortex rope in the draft tube partly overlaps the natural frequencies of the hydropower system. Apart from the vortex rope, the runner rotational frequency is another common frequency that is approximately equal to the frequency of the 10th vibration mode. From the vibration mode shapes, it is inferred that a small disturbance in its frequency close or equal to a specific natural frequency of the vibration mode could induce large pressure oscillations in the tail tunnel. In light of the system’s response to different forcing frequencies, the vortex rope formed under off-design conditions and runner rotational frequency is verified to be the potential exciting source of a traditional hydropower system, and the frequency 0.2 fn is much more dangerous than other disturbances to the system.

scholarly journals Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Luqman S. Maraaba ◽  
Zakariya M. Al-Hamouz ◽  
Abdulaziz S. Milhem ◽  
Ssennoga Twaha
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Efficiency ◽  
Experimental Tests ◽  
Induction Machines ◽  
Test Methods ◽  
Operating Conditions ◽  
Test Method ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

scholarly journals Engine Malfunctioning Conditions Identification through Instantaneous Crankshaft Torque Measurement Analysis

2021 ◽  
Vol 11 (8) ◽  
pp. 3522
Author(s):  
Konstantinos-Marios Tsitsilonis ◽  
Gerasimos Theotokatos
Keyword(s):  
Operating Conditions ◽  
Cylinder Pressure ◽  
Dynamics Model ◽  
Engine Model ◽  
Measurement Analysis ◽  
Start Of Injection ◽  
Rate Of Heat Release ◽  
Relationship Of ◽  
Diagnostic Measurement ◽  
The Relationship

In this study a coupled thermodynamics and crankshaft dynamics model of a large two-stroke diesel engine was utilised, to map the relationship of the engine Instantaneous Crankshaft Torque (ICT) with the following frequently occurring malfunctioning conditions: (a) change in Start of Injection (SOI), (b) change in Rate of Heat Release (RHR), (c) change in scavenge air pressure, and (d) blowby. This was performed using frequency analysis on the engine ICT, which was obtained through a series of parametric runs of the coupled engine model, under the various malfunctioning and healthy operating conditions. This process demonstrated that engine ICT can be successfully utilised to identify the distinct effects of malfunctions (c) or (d), as they occur individually in any cylinder. Furthermore by using the same process, malfunctions (a) and (b) can be identified as they occur individually for any cylinder, however there is no distinct effect on the engine ICT among these malfunctions, since their effect on the in-cylinder pressure is similar. As a result, this study demonstrates the usefulness of the engine ICT as a non-intrusive diagnostic measurement, as well as the benefits of malfunctioning conditions mapping, which allows for quick and less resource intensive identification of engine malfunctions.

scholarly journals Sensitivity Analysis of OTEC-CC-MX-1 kWe Plant Prototype

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2585
Author(s):  
Jessica Guadalupe Tobal-Cupul ◽  
Estela Cerezo-Acevedo ◽  
Yair Yosias Arriola-Gil ◽  
Hector Fernando Gomez-Garcia ◽  
Victor Manuel Romero-Medina
Keyword(s):  
Sensitivity Analysis ◽  
Experimental Tests ◽  
Caribbean Sea ◽  
Ocean Model ◽  
Operating Conditions ◽  
Working Fluid ◽  
Ocean Energy ◽  
Mexican Caribbean ◽  
Water Temperature Data ◽  
Mass Flows

The Mexican Caribbean Sea has potential zones for Ocean Thermal Energy Conversion (OTEC) implementation. Universidad del Caribe and Instituto de Ciencias del Mar y Limnologia, with the support of the Mexican Centre of Innovation in Ocean Energy, designed and constructed a prototype OTEC plant (OTEC-CC-MX-1 kWe), which is the first initiative in Mexico for exploitation of this type of renewable energy. This paper presents a sensitivity analysis whose objective was to know, before carrying out the experimental tests, the behavior of OTEC-CC-MX-1 kWe regarding temperature differences, as well as the non-possible operating conditions, which allows us to assess possible modifications in the prototype installation. An algorithm was developed to obtain the inlet and outlet temperatures of the water and working fluid in the heat exchangers using the monthly surface and deep-water temperature data from the Hybrid Coordinate Ocean Model and Geographically Weighted Regression Temperature Model for the Mexican Caribbean Sea. With these temperatures, the following were analyzed: fluctuation of thermal efficiency, mass flows of R-152a and water and power production. By analyzing the results, we verified maximum and minimum mass flows of water and R-152a to produce 1 kWe during a typical year in the Mexican Caribbean Sea and the conditions when the production of electricity is not possible for OTEC-CC-MX-1 kWe.

The analysis on the influence of mixed sliding-rolling motion mode to precision degradation of ball screw

2021 ◽  
pp. 095440622098201
Author(s):  
Qiang Cheng ◽  
Baobao Qi ◽  
Hongyan Chu ◽  
Ziling Zhang ◽  
Zhifeng Liu ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Ball Screw ◽  
Rolling Motion ◽  
Degradation Model ◽  
Sliding Motion ◽  
Factors Analysis ◽  
Motion Mode

The combination of sliding/rolling motion can influence the degree of precision degradation of ball screw. Precision degradation modeling and factors analysis can reveal the evolution law of ball screw precision. This paper presents a precision degradation model for factors analysis influencing precision due to mixed sliding-rolling motion. The precision loss model was verified through the comparison of theoretical models and experimental tests. The precision degradation due to rolling motion between the ball and raceway accounted for 29.09% of the screw precision loss due to sliding motion. Additionally, the total precision degradation due to rolling motion accounted for 21.03% of the total sliding precision loss of the screw and nut, and 17.38% of the overall ball screw precision loss under mixed sliding-rolling motion. In addition, the effects of operating conditions and structural parameters on precision loss were analyzed. The sensitivity coefficients of factors influencing were used to quantitatively describe impact degree on precision degradation.

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