Modelling of the Cross Angle and its Impact on Pump Performance

2021 ◽  
Author(s):  
Andris Rambaks ◽  
Katharina Schmitz
Keyword(s):  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Great Success ◽  
Pump Performance ◽  
Flow Ripple ◽  
The Past ◽  
Swash Plate ◽  
Simulation Results ◽  
The Cross ◽  
Pressure Controlled

Abstract A secondary swash plate angle, also known as a cross angle, has been used in the past to reduce flow ripple with great success. However, for the past two decades, research in this field has been scarce. In this paper, a pressure controlled 9-piston pump is investigated to determine the effects of the cross angle on commutation, acting forces and torques, as well as volumetric flow rate pulsations. A detailed description of the piston kinematics, the simulation model used, and the subsequent simulation results are presented in this contribution.

Optimization of an Innovative Rotary Shaft Pump (RSP)

2006 ◽  
Vol 128 (6) ◽  
pp. 1281-1288 ◽  
Author(s):  
Jacob C. Allen ◽  
Phillip M. Ligrani
Keyword(s):  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Maximum Flow ◽  
Performance Data ◽  
Outer Diameter ◽  
Hydraulic Efficiency ◽  
Rotary Pump ◽  
Optimal Arrangement ◽  
Pump Performance ◽  
Pump Head

This paper describes the optimization of rotary shaft pump performance, which is accomplished by comparing the performance of four different centrifugal rotary pump configurations: hooked blades pump, backward-curved blades ID=12.7mm pump, contoured base pump, and backward-curved blades ID=19.1mm pump. Each of these devices utilizes a unique and simple impeller design where the blades are directly integrated into a shaft with an outer diameter of 25.4mm. Presented for each pump are performance data including volumetric flow rate, pump head, and hydraulic efficiency. When pumping water, the most optimal arrangement with the hooked impeller blades produces a maximum flow rate of 3.22L∕min and a pump head as high as 0.97m.

Kinematic Analysis of a Swash-Plate Controlled Variable Displacement Axial-Piston Pump With a Conical Barrel Assembly

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Zhiru Shi ◽  
Gordon Parker ◽  
Jonathan Granstrom
Keyword(s):  
High Pressure ◽  
Frequency Analysis ◽  
Flow Rate ◽  
Piston Pump ◽  
Flow Ripple ◽  
Swash Plate ◽  
Piston Displacement ◽  
Output Flow ◽  
Variable Displacement ◽  
Axial Piston

Variable displacement, swash-plate controlled, axial-piston pumps are widely used in applications that require high pressure and variable flow rates. The pump consists of a rotating barrel assembly that houses several pistons in a circular array. A swash-plate is used to control the displacement of the pistons to adjust the output flow of hydraulic fluid. As the barrel rotates, the pistons slide along the angled swash-plate and draw oil from the supply and then discharge oil into the high pressure circuit. This results in an almost constant output flow rate. This paper analyzes the kinematics of a pump based on its geometry dependent characteristics. The analysis assumes an idealized case in which there is no oil leakage and the fluid is considered to be incompressible. It is revealed through the analysis that the piston displacement and the pump output flow are slightly increased by using a conical barrel. Instantaneous and mean flow rate equations are used to describe the output flow characteristics and flow ripple effect. The output flow rate ripple profile is found to be a function of both swash-plate angle and the conical barrel angle. A term defined as the flow rate uniformity coefficient is used to better quantify the flow ripple phenomenon. A frequency analysis is performed on the output flow rate and an additional order is found to be present when using a conical barrel pump versus one with a cylindrical barrel when the pumps have an odd number of pistons. Conical barrel piston pumps are found to have a slight increase in piston displacement, velocity, and acceleration relative to the rotating barrel frame of reference over a pump with a cylindrical barrel. This translates into an increase in the output flow rate for a conical piston pump under the same operating conditions. The conical barrel is also found to have a reduction in the rotational inertia allowing for faster angular acceleration. The presence of an extra order from a frequency analysis for a conical pump with an odd number of pistons has the potential to cause unwanted noise or vibration to the structure or components attached to the pump.

The Influence of Cross Angle on the Flow Ripple of Axial Piston Pumps by CFD Simulation

2012 ◽  
Vol 220-223 ◽  
pp. 1675-1678 ◽  
Author(s):  
Xiu Ye Wei ◽  
Hai Yan Wang
Keyword(s):  
Noise Reduction ◽  
Cfd Simulation ◽  
Rotation Angle ◽  
Piston Pump ◽  
Flow Pulsation ◽  
Flow Ripple ◽  
Axial Piston Pumps ◽  
Swash Plate ◽  
The Cross ◽  
Axial Piston

This paper studies the flow pulsation of axial piston pumps of different cross angles based on CFD simulation. The swash-plate cross angle of piston pump affects the piston pump outlet flow pulsation by changing the contraction amount of the plunger in the valve plate transition zone. First, we established the flow pulsation model with swash plate cross angle based on the noise reduction principle of the swash plate cross angle, and studied the influence of cross angle of different rotation angels on the flow pulsation based on CFD simulation. The conclusion is that the maximum and minimum peak of the flow pulsation decreased when the rotation angle of the cross angle is greater than 1 °; the maximum and minimum peak of the flow pulsation increased when the rotation angle of the cross angle is less than -1 °; a good noise reduction can be got when the piston pump cross angle rotates 1°.

Characteristics of the Diffuser/Nozzle Valve-Less Micro-Pump

2007 ◽  
Author(s):  
Seiichi Tanaka ◽  
Hiroshi Tsukamoto ◽  
Koji Miyazaki
Keyword(s):  
Reynolds Number ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Simplified Model ◽  
Working Fluid ◽  
Oscillating Flow ◽  
Fluid Viscosity ◽  
Pump Performance ◽  
Micro Pump ◽  
Pump Head

In this study we have developed a valve-less micro-pump with one diffuser shaped element and a chamber with a diaphragm; the vibration of which produces an oscillating flow. The pressure-loss in a nozzle is lower than that in a diffuser, and therefore one-way flow is realized in the nozzle direction. The frequency characteristics and the pump characteristics are measured. The maximum total pump head and volumetric flow rate are 0.8 kPa and 2.4 ml/min respectively. The effect of working-fluid viscosity on pump characteristics is also discussed using water and glycerin-water solutions. As a result, the pump performances were found to decrease with increasing fluid viscosity and the pump performance depended on the Reynolds number of oscillating flow. The experimental results are discussed using a simplified model based on the Bernoulli’s theory for unsteady flow in pump.

The pumping characteristics of screw rotors. I. The theory of calculation of the pumping capacity of screw rotors

1987 ◽  
Vol 52 (2) ◽  
pp. 357-371 ◽  
Author(s):  
František Rieger
Keyword(s):  
Present State ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Screw Rotor ◽  
Screw Rotors

This paper summarizes the present state of the theory of calculation of the pumping capacity of screw rotors. The calculation starts from the equation for the volumetric flow rate of the flow between two unconfined plates modified by correction coefficients obtained from the relationships for the flow rate in simpler geometrical configurations to which the screw rotor may be, under certain circumstances, reduced.

Assessment of the Use of Humidified Nasal Cannulas for Oxygen Therapy in Patients with Epistaxis

ORL ◽  
2021 ◽  
pp. 1-5
Author(s):  
Jingjing Liu ◽  
Tengfang Chen ◽  
Zhenggang Lv ◽  
Dezhong Wu
Keyword(s):  
Flow Rate ◽  
Oxygen Therapy ◽  
Preliminary Investigation ◽  
Nasal Cannula ◽  
Low Flow ◽  
Antiplatelet Drugs ◽  
Flow Rates ◽  
The Past ◽  
Oxygen Inhalation ◽  
Significant Difference

<b><i>Introduction:</i></b> In China, nasal cannula oxygen therapy is typically humidified. However, it is difficult to decide whether to suspend nasal cannula oxygen inhalation after the nosebleed has temporarily stopped. Therefore, we conducted a preliminary investigation on whether the use of humidified nasal cannulas in our hospital increases the incidence of epistaxis. <b><i>Methods:</i></b> We conducted a survey of 176,058 inpatients in our hospital and other city branches of our hospital over the past 3 years and obtained information concerning their use of humidified nasal cannulas for oxygen inhalation, nonhumidified nasal cannulas, anticoagulant and antiplatelet drugs, and oxygen inhalation flow rates. This information was compared with the data collected at consultation for epistaxis during these 3 years. <b><i>Results:</i></b> No significant difference was found between inpatients with humidified nasal cannulas and those without nasal cannula oxygen therapy in the incidence of consultations due to epistaxis (χ<sup>2</sup> = 1.007, <i>p</i> &#x3e; 0.05). The same trend was observed among hospitalized patients using anticoagulant and antiplatelet drugs (χ<sup>2</sup> = 2.082, <i>p</i> &#x3e; 0.05). Among the patients with an inhaled oxygen flow rate ≥5 L/min, the incidence of ear-nose-throat (ENT) consultations due to epistaxis was 0. No statistically significant difference was found between inpatients with a humidified oxygen inhalation flow rate &#x3c;5 L/min and those without nasal cannula oxygen therapy in the incidence of ENT consultations due to epistaxis (χ<sup>2</sup> = 0.838, <i>p</i> &#x3e; 0.05). A statistically significant difference was observed in the incidence of ENT consultations due to epistaxis between the low-flow nonhumidified nasal cannula and nonnasal cannula oxygen inhalation groups (χ<sup>2</sup> = 18.428, <i>p</i> &#x3c; 0.001). The same trend was observed between the 2 groups of low-flow humidified and low-flow nonhumidified nasal cannula oxygen inhalation (χ<sup>2</sup> = 26.194, <i>p</i> &#x3c; 0.001). <b><i>Discussion/Conclusion:</i></b> Neither high-flow humidified nasal cannula oxygen inhalation nor low-flow humidified nasal cannula oxygen inhalation will increase the incidence of recurrent or serious epistaxis complications; the same trend was observed for patients who use anticoagulant and antiplatelet drugs. Humidification during low-flow nasal cannula oxygen inhalation can prevent severe and repeated epistaxis to a certain extent.

Pahoehoe and aa in Hawaii: volumetric flow rate controls the lava structure

1990 ◽  
Vol 52 (8) ◽  
pp. 615-628 ◽  
Author(s):  
Scott K Rowland ◽  
George PL Walker
Keyword(s):  
Flow Rate ◽  
Volumetric Flow Rate

Simultaneous Measuring Method for Both Volumetric Flow Rates of Air-Water Mixture Using a Turbine Flowmeter

1996 ◽  
Vol 118 (1) ◽  
pp. 29-35 ◽  
Author(s):  
K. Minemura ◽  
K. Egashira ◽  
K. Ihara ◽  
H. Furuta ◽  
K. Yamamoto
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Oil Field ◽  
Liquid Density ◽  
Water Mixture ◽  
Rotor Speed ◽  
Flow Rates ◽  
Field Development ◽  
Turbine Flowmeter

A turbine flowmeter is employed in this study in connection with offshore oil field development, in order to measure simultaneously both the volumetric flow rates of air-water two-phase mixture. Though a conventional turbine flowmeter is generally used to measure the single-phase volumetric flow rate by obtaining the rotational rotor speed, the method proposed additionally reads the pressure drop across the meter. After the pressure drop and rotor speed measured are correlated as functions of the volumetric flow ratio of the air to the whole fluid and the total volumetric flow rate, both the flow rates are iteratively evaluated with the functions on the premise that the liquid density is known. The evaluated flow rates are confirmed to have adequate accuracy, and thus the applicability of the method to oil fields.

Development of Cooling System for a Large Area at High Heat Flux by Using Flow Boiling in Narrow Channels

2009 ◽  
Author(s):  
Shinichi Miura ◽  
Yukihiro Inada ◽  
Yasuhisa Shinmoto ◽  
Haruhiko Ohta
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Rate ◽  
Mass Velocity ◽  
Cooling System ◽  
Volumetric Flow Rate ◽  
High Heat ◽  
High Heat Flux ◽  
Gap Size ◽  
Heated Channel

Advance of an electronic technology has caused the increase of heat generation density for semiconductors densely integrated. Thermal management becomes more important, and a cooling system for high heat flux is required. It is extremely effective to such a demand using flow boiling heat transfer because of its high heat removal ability. To develop the cooling system for a large area at high heat flux, the cold plate structure of narrow channels with auxiliary unheated channel for additional liquid supply was devised and confirmed its validity by experiments. A large surface of 150mm in heated length and 30mm in width with grooves of an apex angle of 90 deg, 0.5mm depth and 1mm in pitch was employed. A structure of narrow rectangular heated channel between parallel plates with an unheated auxiliary channel was employed and the heat transfer characteristics were examined by using water for different combinations of gap sizes and volumetric flow rates. Five different liquid distribution modes were tested and their data were compared. The values of CHF larger than 1.9×106W/m2 for gap size of 2mm under mass velocity based on total volumetric flow rate and on the cross section area of main heated channel 720kg/m2s or 1.7×106W/m2 for gap size of 5mm under 290kg/m2s were obtained under total volumetric flow rate 4.5×10−5m3/s regardless of the liquid distribution modes. Under several conditions, the extensions of dry-patches were observed at the upstream location of the main heated channel resulting burnout not at the downstream but at the upstream. High values of CHF larger than 2×106W/m2 were obtained only for gap size of 2mm. The result indicates that higher mass velocity in the main heated channel is more effective for the increase in CHF. It was clarified that there is optimum flow rate distribution to obtain the highest values of CHF. For gap size of 2mm, high heat transfer coefficient as much as 7.4×104W/m2K were obtained at heat flux 1.5×106W/m2 under mass velocity 720kg/m2s based on total volumetric flow rate and on the cross section area of main heated channel. Also to obtain high heat transfer coefficient, it is more useful to supply the cooling liquid from the auxiliary unheated channel for additional liquid supply in the transverse direction perpendicular to the flow in the main heated channel.

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