Pump Flow Rate Research Articles

Development of an IOT based Solenoid Controlled Pressure Regulation System for Precision Sprayer

Abstract: In recent years, Precision Agriculture has embarked a promising role in augmenting agricultural production and various farm mechanization. The present research was conducted to design and develop a Precision Spraying System (PSS) that is controlled by an Automatic Control System (ACS). PSS was equipped with micro-controller (NodeMCU), an analog pressure regulator, solenoid valve, diaphragm pump coupled with 12V DC motor; operated on a Iot platform BLYNK. A 3D printed full cone nozzle (0.2 mm orifice dia., cone angle of 95°) was designed to achieve desired spraying efficacy as per the canopy area and the need of the crop cultivated. Integration of PSS with ACS, intrigues a proper regulation on the valves (24V, 7.92W), the pump speed, pressure head and flow rates. The spray patternator test was conducted to evaluate the Delay Time Losses (DTL), application losses, effective spraying height and pressure. The test was conducted for 4 sets of increasing pressure (5.46, 6.24, 6.86 and 7.80 bar) and 3 sets of decreasing nozzle heights (890, 760 and 620 mm). The results revealed that the maximum average discharge collected from the Patternator tray was 0.45L/min (at pressure 7.80 bar; height 620 mm) and the minimum average discharge collected was 0.26 L/min (at pressure 5.46 bar; height 890 mm). The spray angle was found to vary from 72 to 82° and the percent (%) loss in discharge was estimated to maximum of 49.02% (at height 890 mm) and the minimum value of 11.76% (at height of 620 mm) suggesting possible wind drift with increasing nozzle height. Thus, the designed PSS is propitious to forefend all the ill effects of conventional spraying and it significantly reduces the DTL to 0.5 sec

Design and fluid analysis of the microsegment gear tooth profile for pump operating at high speed and high pressure

In order to solve the problem of oil trapping in involute gear pumps, a new tooth profile based on the microsegment tooth profile and incorporating the circular arc tooth profile theory has been designed in this study. Firstly, the tooth profile equation of the microsegment gear profile for the pump has been derived. Then, the spatial tooth surface equation of the helical microsegment gear for the pump has been derived, and the feasibility of the new tooth profile has been verified using the contact spot experiment. The characteristics of the new gear profile without oil trapping and the closed “8” type mesh line have been analyzed, from which the output flow rate of the microsegment gear pump has been verified to be constant. A conclusion has been drawn on the applicability of the microsegment gear tooth profile for the pumps. Further, the fluid analysis model of the microsegment gear pump has been proposed to analyze the oil pressure distribution and state of fluid motion at high pressures in the microsegment gear pump. A comparison of the performances of the involute and the microsegment gear pumps shows that the output pressure and maximum pressures of the microsegment gear pump are smoother than that of the involute gear pump. Analysis of the effect of the high rotational speed on the output oil pressure and the maximum pressure shows that the former increases, whereas the latter varies very little with the rotational speed.

Ultrasound vector flow imaging during veno-arterial extracorporeal membrane oxygenation in a thoracic aorta model

In veno-arterial extracorporeal membrane oxygenation (VA-ECMO) treatment, the mixing zone is a key hemodynamic factor that determines the efficacy of the treatment. This study aimed to evaluate the applicability of a novel ultrasound technique called vector flow imaging (VFI) for visualizing complex flow patterns in an aorta phantom under VA-ECMO settings. VFI experiments were performed to image aortic hemodynamics under VA-ECMO treatment simulated in an anthropomorphic thoracic aorta phantom using a pulsatile pump (cardiac output: 2.7 L/min) and an ECMO pump with two different flow rates, 0.35 L/min and 1.0 L/min. The cardiac cycle of hemodynamics in the ascending aorta, aortic arch, and descending aorta was visualized, and the spatio-temporal dynamics of flow vectors were analyzed. VFI successfully visualized dynamic flow patterns in the aorta phantom. When the flow rate of the ECMO pump increased, ECMO flow was more dominant than cardiac output in the diastole phase, and the speed of cardiac output was suppressed in the systole phase. Vortex flow patterns were also detected in the ascending aorta and the arch under both ECMO flow rate conditions. The VFI technique may provide new insights into aortic hemodynamics and facilitates effective and safe VA-ECMO treatment.

Simulation Analysis of a Novel Digital Pump with Direct Recycling of Hydraulic Energy

There is a permanent and strong need for energy recovery to improve the efficiency of the hydraulic system in the field of the construction machinery. In addition, the digital pump will become powerful and versatile by employing different configurations and intelligent control of the flow distribution valves. Considering this case, we have proposed a novel digital pump in which every plunger is equipped with two flow distribution valves. By controlling these two valves, external hydraulic energy can be directly reused without other components. Based on the structure and working principle of the digital pump, the mathematical model is established and three working modes are detailed. To verify the feasibility and correctness of control methods, a performance simulation testing platform including a digital pump, load module, hydraulic energy to be recovered, and controller module was developed in AMESim R15 software. The pressure, flow rate, and torque simulations of the digital pump in three working modes were carried out. The simulation results have shown that the digital pump not only can be used as an ordinary pump but also has the function of recovery and immediate reutilization of another hydraulic energy. Meanwhile, the corresponding variable displacement control strategy is effective and the positive torque required to drive the digital pump can be reduced, which verified the energy-saving of this scheme. The ideas and contents in this paper can offer significant references for energy conservation technology of various engineering machineries and the intensive study of digital hydraulics.

Practical Approach for Defining the Sustainable Yield of Wells in Low-Permeability Fractured Rocks

Groundwater sustainability is still an open question. Theoretical and practical approaches to the definition of groundwater sustainability were mainly developed on large scales, while few studies are available for its definition at a single well scale, especially in fractured aquifers. This study examines how much the sustainable yield of a well in fractured aquifers depends on the trend of drawdown over time. For this aim, pumping tests conducted in fractured rocks were considered and analytical models were applied to examine the long-term response of groundwater levels in some wells. To define the operational pumping flow of a well in these aquifers, results show that long constant flow rate pumping tests are preferred to step-drawdown tests. The late drawdown–time curve and residual drawdown segment-curves during the recovery, approximated by power, exponential or polynomial equations, represent the first step to extrapolating the long-term drawdown in the well. This prediction combined with the assessment of a drawdown limit in the well (as a function of the saturated thickness of the aquifer) are essential to plan the first operation of the well (flow rate and time of pumping). Subsequently, through the monitoring of this first operation step, the following operation phases can be updated and improved.

Soft computing-based predictive modeling of flexible electrohydrodynamic pumps

Flexible electrohydrodynamic (EHD) pumps have been developed and applied in many fields due to no transmission structure, no wear, easy manipulation, and no noise. Physical simulation is often used to predict the output performance of flexible EHD pumps. However, this method neglects fluid–solid interaction and energy loss caused by flexible materials, which are both difficult to calculate when the flexible pumps deform. Therefore, this study proposes a flexible pump output performance prediction using machine learning algorithms. We used three different types of machine learning: random forest regression, ridge regression, and neural network to predict the critical parameters (pressure, flow rate, and power) of the flexible EHD pump. Voltage, angle, gap, overlap, and channel height are selected as five input data of the neural network. In addition, we optimized essential parameters in the three networks. Finally, we adopt the best predictive model and evaluate the significance of five input parameters to the output performance of the flexible EHD pumps. Among the three methods, the MLP model has exceptionally high accuracy in predicting pressure and flow. Our work is beneficial for the design process of fluid sources in flexible soft actuators and soft hydraulic sources in microfluidic chips.

Hydrodynamic Characteristic Analysis and NSGA-II Optimization of a Vacuum Fish Pump

The fish pump is an important piece of power equipment for aquaculture, especially for deep-sea engineering vessels and cage culture. Fish pump research focuses on reducing fish body damage, improving survival rates, and increasing fish lifting efficiency. The research object in this paper is a new type of vacuum fish pump, with the aim of improving the hydraulic performance of the vacuum fish pump and reducing the damage to the fish body. The dependent variables include the dynamic change process of the flow state and flow field under diachronic conditions, the fluid simulation analysis of the vacuum pump body and the flow channel structure, the inlet flow rate of the fish pump, the negative pressure of the pipeline, and the impact force of the water flow on the inner wall of the tank. The independent variables include the operating conditions of the pump body and the fish pump. The Latin hypercube sampling method is used to extract 167 sets of calculation models for the independent variables, and multi-objective optimization is performed based on the NSGA-II algorithm for the hydrodynamic performance of the fish pump. On the basis of ensuring the fish body damage rate, the structural parameters of the vacuum fish pump with the optimal hydrodynamic performance under 167 sets of parameter values were obtained. The optimized parameters were then entered into the solver again, and the results showed that, in the optimal structural parameters under certain conditions, the direction of the incident water flow in the vacuum fish pump tank is close to the upper end of the tank body, which will reduce the speed of the fish-water mixed flow when entering the tank, thereby reducing the collision damage to the fish body. Currently, the water flow velocity at the water inlet is about 2.5 m/s, and the negative pressure value distribution gradient between the tank body and the water inlet pipeline is quite consistent, which can achieve good fish suction and fish lifting effects.

Development of a High Flow Rate Soft Pump Driven by Intersected Twisted Artificial Muscles Units

Small soft pumps are extensively explored in medical fields and soft robotics, but the insufficient flow rate constrains their applications. In this article, an intersected twisted artificial muscle unit (ITAMU) is proposed to achieve a large contraction ratio, which is adapted to drive the developed soft pump, and characteristics of high flow rate and no noise pollution are achieved. The configuration and principle of the ITAMU and the soft pump are depicted. Besides, the contraction ratio of ITAMU and the flow rate of the soft pump are calculated theoretically. Then, the prototypes are manufactured and tested. The results indicate that the maximum contraction ratio of ITAMU reaches 41.2%, and the output force is 3.27 N. Ultimately, the experiments on the flow rate and pressure of the soft pump are carried out. The maximum flow rate is 680 mL/min, and the pressure reaches 2.3 kPa. To sum up, the proposed soft pump exhibits a high flow rate, which shows its application prospect in the field like soft exploration robots.

Outcomes After Deceased Donor Kidney Transplantation Using Kidney Allografts With Marginal Perfusion Parameters

This study examines outcomes of deceased donor kidney transplantation (DDKT) in recipients of kidney allografts with marginal perfusion parameters. Allografts with marginal perfusion parameters (resistance index [RI] >0.4 and pump flow rate [F] <70 mL/min; MP group) were compared with those with good parameters (RI <0.4 and F >70 mL/min; GP group) for DDKT recipients between January 1996 and November 2017 after hypothermic pulsatile perfusion. Demographics, creatinine, cold ischemia times (CIT), delayed graft function (DGF), and recipient glomerular filtration rate at pre- and post-transplant were noted. The primary outcome was graft survival post-transplant. In the MP (n=31) versus GP (n=1281) group, the median recipient was aged 57 years versus 51 years; the median donor was aged 47 versus 37 years; terminal creatinine was 0.9 versus 0.9 mg/dL; CIT was 10.2 versus 13 hours, and the RI and flow were 0.46 and 60 mL/min versus 0.21 and 120 mL/min. The DGF rate was 19% (MP) versus 8% (GP). The graft survival in the MP versus GP group was 81% versus 90% (1 year), 65% versus 79% (3 years), 65% versus 73% (4 years), and 45% versus 68% (5 years). Carefully selected kidney allografts after comprehensive donor and recipient evaluation may allow for the use of these routinely discarded kidneys with marginal perfusion parameters.

High Performance Liquid Chromatography with Size Exclusion Column (HPLC-SEC) Method for Identifying the Major Whey Proteins of Whey Protein Products

This study was carried-out: a) to develop a high-performance liquid chromatography with size exclusion column (HPLC-SEC) method for the identification of the major whey proteins from selected whey protein products; and b) use the method to estimate the relative composition of the major whey proteins in different whey protein products.&#x0D; An HPLC Shimadzu (LC-10AD VP liquid chromatograph) with system controller (SCL-10A VP) equipped with a pump and auto-injector (SIL-10AD VP) and UV-vis detector (SPD-10AV) was used in the identification of whey proteins in standards and whey protein products. The size exclusion column (SEC) was a Yarra 3 µm, SEC-3000 Column, 7.8 mm I.D. x 30 cm with a security guard.&#x0D; The HPLC-SEC method was successful in identifying the major whey proteins of the different whey protein products.&#x0D; The β-LG contents had the highest level among the whey proteins for all the whey protein products studied, followed by the α-LA and then IgG in both WPC products. However, the α-LA and IgG of the Procream product had almost the same level which was probably due to a different process used in WPC&#x0D; All the major whey proteins with the highest pump flowrate had the shortest elution times while the whey proteins with the lowest pump flowrate had the longest elution times. The optimal pump flowrate was 0.75 mL/min since it gave a faster analysis but differentiate the peaks of the different major whey proteins.

Study of Hydrodnamic Pumping Effects of Fixed Axis Rotation in Eccentric Annular Flow Field

Hydrodynamic effect is one of the key phenomena in journal bearing lubrication. Many researches have been carried out on the supporting force of journal bearing, the motion of suspension shaft and the lubrication effect. This paper studies the hydrodynamic effect from another point of view, that is, the pumping effect caused by the rotation of the eccentric shaft with fixed axis. The clearance between the rotor and the stator is divided into two sections by the inlet port and the outlet port. Their mathematical models are established and studied in polar coordinates. The pressure distribution and pumping flowrate in the flow field are studied theoretically. Under the conditions analyzed in this paper, an output flow larger than 90 ml/s could be generated, overcoming a load pressure of 0.5 MPa. In addition, the pressure distribution and pumping flowrate of the mechanism are affected by the pumping outlet orientation. According to the analysis results of the output angle range from π/8 to 3π/4, when the pump outlet angle is set near 3π/8 to π/2, the pumping flowrate reaches the maximum value of 91.83 ml/s, and nearly half 48% of the inflow liquid can be pumped out to the outlet.

Effects of upward flow rate and modified biochar location on the performance and microecology of an anaerobic reactor treating kitchen waste.

Increasing the value of food waste through anaerobic digestion is an attractive strategy. Meanwhile, the anaerobic digestion of kitchen waste also faces some technical challenges. In this study, four EGSB reactors were equipped with Fe-Mg-chitosan bagasse biochar at different locations, and the reflux pump flow rate was increased to change the upward flow rate of the reactor. The effects of adding modified biochar at different locations under different upward flow rate on the efficacy and microecology of anaerobic reactors treating kitchen waste were investigated. Results showed that Chloroflexi was the dominant microorganism when the modified biochar was added to the lower, middle, and upper parts of the reactor and mixed in the reactor, accounting for 54%, 56%, 58%, and 47%, respectively, on day 45. With the increased upward flow rate, the abundance of Bacteroidetes and Chloroflexi increased, while Proteobacteria and Firmicutes decreased. It was worth noting that the best COD removal effect was achieved when the anaerobic reactor upward flow rate was v2 = 0.6m/h and the modified biochar was added in the upper part of the reactor, during which the average COD removal rate reached 96%. In addition, mixing modified biochar throughout the reactor while increasing the upward flow rate provided the greatest stimulus for the secretion of tryptophan and aromatic proteins in the sludge extracellular polymeric substances. The results provided a certain technical reference for improving the efficiency of anaerobic digestion of kitchen waste and scientific support for the application of modified biochar to the anaerobic digestion process.

Acoustic Atomization-Induced Pumping Based on a Vibrating Sharp-Tip Capillary.

Pumping is an essential component in many microfluidic applications. Developing simple, small-footprint, and flexible pumping methods is of great importance to achieve truly lab-on-a-chip systems. Here, we report a novel acoustic pump based on the atomization effect induced by a vibrating sharp-tip capillary. As the liquid is atomized by the vibrating capillary, negative pressure is generated to drive the movement of fluid without the need to fabricate special microstructures or use special channel materials. We studied the influence of the frequency, input power, internal diameter (ID) of the capillary tip, and liquid viscosity on the pumping flow rate. By adjusting the ID of the capillary from 30 µm to 80 µm and the power input from 1 Vpp to 5 Vpp, a flow rate range of 3 to 520 µL/min can be achieved. We also demonstrated the simultaneous operation of two pumps to generate parallel flow with a tunable flow rate ratio. Finally, the capability of performing complex pumping sequences was demonstrated by performing a bead-based ELISA in a 3D-printed microdevice.

ANALYSIS OF TECHNICAL CHARACTERISTICS OF HIGH TORQUE HYDROMOTORS WITH LIMITATIONS BASED ON DYNAMIC CALCULATIONS

The goal is to study the technical characteristics of the world's largest modern high-torque multi-acting hydraulic motor from the point of view of ensuring reliable operation by the manufacturer at elevated pressures, speeds and depending on the type of working fluid used. Analysis of the influence of dynamic loads on fluctuations in pressure and speed of the hydraulic motor in the modes of starting and braking, taking into account changes in the pump flow rate and inertial loads. Method. Dynamic calculation of a hydraulic fluid power with a high-torque hydraulic motor based on studies of external loads, changes in the pump feed time, providing the maximum speed. To solve nonlinear differential equations when calculating the pressure in the hydraulic drive and the rotational speed of the hydraulic motor, the VisSim application software package was used. The modes of change in the operation of the hydraulic motor over time in terms of rotational speed, pressure in the hydraulic fluid power, output power and hydromechanical efficiency, depending on the external load and pump flow, are presented on the corresponding oscillograms. The mathematical model of the hydraulic fluid power includes simulation modules for controlling the supply of an axial piston pump and changing the moment of resistance on the hydraulic motor. Results. Calculations of the dynamics of a hydraulic fluid power with a high-torque multi-acting radial piston hydraulic motor showed the need for preliminary modeling of its operation modes, taking into account the nature of the external loading, the moment of inertia and the intensity of the pump flow. Conclusion. The conducted studies can be used in the development of hydraulic fluid power with high-torque hydraulic motors to clarify the technological processes of work during the operation of a hydraulic machine.

Modelling of a passive hydraulic lock concept for the mitigation transfer tubes in a SFR core

To improve the safety of the integrated Sodium-cooled Fast Reactor, recent safety complementary devices can prevent or mitigate the consequences of a hypothetical severe accident consecutive to a loss of reactor cooling sequence. In particular, the M−TT device is set by empty transfer tubes, in place of some fuel sub-assemblies present in the reactor core, using an innovative passive hydraulic lock. It is based on the concept of hydraulic diode controlled by the flowrate of primary pumps. This system is dedicated to provide an easy way to discharge corium towards the core catcher in the hypothetical case of severe accident. In bonus, concerning the prevention of severe accident, it opens a direct flow path between the hot pool, equipped with decay heat removal exchangers, and the cold pool. This can lead to an easier passage of colder sodium towards the cold pool to promote core cooling by natural convection in case of the loss of the primary flow. This paper is devoted to the evaluation of the assessment of the hydraulic lock function and of the small magnitudes of the perturbations induced by our device on the thermal–hydraulic behavior of the reactor during normal operations. Through an analytical analysis and an up-scaling numerical approach, ranging from the local scale (CFD) to the system one, we claim that the lock function is kept during the normal situations at various power regimes. The leak flow represents no more than 1% of the primary pump flow. In addition, no important reactor thermal–hydraulic perturbation is brought by adding transfer tubes in the core. This is true for normal steady states, whatever the power is, but also for a full-power loss of forced flow accidental transient leading to the natural convection cooling.

Laboratory studies of fish entrainment sampling using a screw centrifugal impeller pump

AbstractObjectiveRegulatory legislation in both the United States and Canada requires water users with medium to high intake volumes to monitor entrainment losses to determine effects and to assess potential mitigation strategies to reduce harm to fish. Recent studies have recommended the use of both increased sampling frequency and sampling volume to characterize fish entrainment for large power plants on the Great Lakes. There is little doubt that increasing the flow rate and volume of water collected for sampling reduces the uncertainty in estimates of annual entrainment. Depending on the type of pump and the pumping flow rate used for entrainment sampling, considerable damage to fish larvae can occur. A screw‐type centrifugal pump has many qualities that make it ideal for entrainment sampling, but it has not yet been used as a sampling device for fish entrainment applications at power plants or other large industrial water users. The objective of this study was to determine mortality of entrainable fish eggs and larvae due to passage through a screw‐type centrifugal pump.MethodsIn a laboratory setting, Lake Trout Salvelinus namaycush eggs and larvae, Lake Whitefish Coregonus clupeaformis eggs, and Rainbow Trout Oncorhynchus mykiss juveniles were passed through a screw‐type centrifugal pump at three treatment flow rates: 39.5, 47.3, and 59.1 m3/h. Fish and eggs were monitored for mortality posttreatment and again at 24 and 48 h.ResultAcross treatments, very few mortalities were observed. Species specific moralities were four larval Lake Trout, one Lake Whitefish egg, and one juvenile Rainbow Trout. No mortality was observed for Lake Trout eggs.ConclusionThe present study identified high egg and larval survival (≥99%) after passage through a screw‐type centrifugal pump. High survival reduces error associated with identification and counting of entrained organisms, which provides more accurate estimates of annual entrainment losses.

BIO14: Platelet energy metabolism in an in-vitro ECMO model

Background: Extracorporeal membrane oxygenation (ECMO) exposes blood to mechanical shear stress and artificial surfaces, leading to platelet activation and thrombosis. We hypothesize that ECMO-induced platelet activation leads to changes in platelet energy metabolism. Methods: Based on an in vitro ECMO model (Cardiohelp platform; HLS Advanced 5.0 Oxygenator), human whole blood was circulated at low (1 L/min) or nominal flow (4L/min) for 6 hours. A static control sample was drawn after priming and held in the same tubing at 37 °C. Experiments were terminated if clot formation caused device failure. Samples were drawn at baseline as well as hourly throughout the experiment (T0 – T6) and assessed for cell counts and intracellular levels of bioenergetic intermediates, which were normalized to platelet count. Results: Preliminary data documents that 83% of ECMO runs completed 6 hours of perfusion. One nominal ECMO run was terminated due to clot formation after 5 hours. We found a statistically significant difference in platelet ATP levels after 6 hours between the control and the nominal group (181 nM ± 13 vs 107 nM ± 11, p = 0.02). Furthermore, we saw a statistically significant difference in ADP levels at T6 between the control group and the nominal group (517 nM ± 45 vs 255 nM ± 16, p = 0.001) as well as between the control group and the low-flow-group (330 nM ± 9, p = 0.001). We observed a trend in difference between low and nominal flow groups for ATP and ADP. Conclusion: This preliminary analysis indicates that ECMO pump flow rate effects on ATP and ADP levels in platelets. These insights into energy metabolism in platelets exposed to ECMO might lead to novel therapeutical approaches to prevent clotting events during ECMO.

A Smart Active Phase-Change Micropump Based on CMOS-MEMS Technology.

The rational integration of many microfluidic chips and micropumps remains challenging. Due to the integration of the control system and sensors in active micropumps, they have unique advantages over passive micropumps when integrated into microfluidic chips. An active phase-change micropump based on complementary metal-oxide-semiconductor-microelectromechanical system (CMOS-MEMS) technology was fabricated and studied theoretically and experimentally. The micropump structure is simple and consists of a microchannel, a series of heater elements along the microchannel, an on-chip control system, and sensors. A simplified model was established to analyze the pumping effect of the traveling phase transition in the microchannel. The relationship between pumping conditions and flow rate was examined. Based on the experimental results, the maximum flow rate of the active phase-change micropump at room temperature is 22 µL/min, and long-term stable operation can be achieved by optimizing heating conditions.

Dual Synthetic Jets Actuator and Its Applications Part V: Novel Valveless Continuous Micropump Based on Dual Synthetic Jets with a Tesla Structure

The valveless micropump based on dual synthetic jets is a potential fluid pumping device that has the ability to transport fluid continuously. In order to improve the performance of this device, a novel valveless continuous micropump based on dual synthetic jets with a Tesla structure was proposed by combining a double Tesla symmetrical nozzle and a dual synthetic jets actuator. The mechanism of the novel micropump and its flow field characteristics were analyzed, combined with numerical simulation and a PIV experiment. The performance of the novel micropump was compared with that of a dual synthetic jet micropump based on a traditional shrinking nozzle. The novel micropump achieved continuous flow with a larger and more stable flow rate in one cycle. The maximum pump flow speed reached 12 m/s. Compared with the traditional type, the pump flow rate was increased by 5.27% and the pump flow pulsation was reduced by 214.93%. The backflow and vortex inside the nozzle were prevented and inhibited effectively by the Tesla structure. The velocity and influence range of the pump flow increased with the intensification of driving voltage in a certain range.

Experimental and Numerical Study on Cavitation Effects in Centrifugal Pumps

Experimental and numerical investigations of the centrifugal pump performance at non-cavitating and cavitating flow conditions were carried out in the present study. Experiments were performed by applying a vacuum to a closed-loop system to investigate the effects of the net positive suction head available (NPSHa), flow rate, water temperature and pump speed on the centrifugal pump performance. Accordingly, many of the important parameters concerning cavitation phenomenon were calculated. Also, the noise which is accompanied by cavitation was measured. Numerical analysis was implemented for two phase flow (the water and its vapor) using a 2-D simulation by ANSYS FLUENT software to investigate the internal flow of centrifugal pump under cavitating conditions. It was observed that with decreasing NPSHa, the values of the pump head, flow rate and efficiency initially remain constant, but with further reduction in NPSHa these parameters will decrease. Also, it was found that at 3% head drop the percentage drop of the flow rate is less than 2% whereas the percentage drop of the efficiency is greater than 3%. Numerically, it was noticed that the cavitation regions appear at the leading edge of suction side of the impeller blades which represents the lowest pressure area inside the computational domain of the centrifugal pump.