Vertical Pump Research Articles

Analysis of internal flow characteristics and structure optimization of vertical submersible axial flow pump device

In order to investigate the internal flow characteristics and hydraulic stability of vertical submersible pump station in forward and reverse operation, the steady and unsteady three-dimensional numerical simulation of vertical submersible axial-flow pump device was carried out based on CFD and the energy performance of the pump device was predicted. In this paper, the internal flow characteristics of the vertical submersible axial-flow pump device under forward and reverse operation were analyzed, and the optimization of the structure passed by water was carried out to improve the efficiency of the pump device in forward and reverse operation. The results show that the performance of the pump device is good when it is running in the forward direction, the peak efficiency of the pump device is 72.22% and the corresponding head is 4.01 m. When it is running in the reverse direction, the performance of the pump device decreases significantly with the peak efficiency is only 36.03% and the corresponding head is 3.34 m. The hydraulic loss in the dust-pan-shaped conduit is very small in the forward operation, the wellbore conduit is the main factor which affects the efficiency of the submersible axial flow pump device, the loss ratio is 12%–44%. When the pump device is in reverse operation, the hydraulic loss is similar but the hydraulic performance is poor and the hydraulic loss is obviously larger than that in forward operation. A guide plate is added to the dust-pan-shaped conduit at 0.27 D ( D is the nominal diameter of impeller) along the axis direction of the conduit, and a elbow flow conduit with the corner radius R of 0.83 D is selected to replace the wellbore conduit, the bad flow state disappeared and the efficiency of the pump device increased by 5.19% in the forward operation while the efficiency of the pump device increased by 9.62% in the reverse operation.

Harvesting conductive heat loss of interfacial solar evaporator for thermoelectric power generation

• The conductive heat loss of an interfacial photothermal evaporator is harvested. • The evaporation rate is up to 4.51 kg m -2 h −1 with excellent salt-resistance. • The device obtains a considerable power density of 1.2 W m −2 at 4 suns. • The output current becomes stable within 2 min if the light intensity is changed. The solar-driven interfacial water evaporation technique enables to sustainably produce potable water from sewage, wastewater, and seawater. Limited by the advanced functional materials and structures, however, the contradiction between high evaporation rate and low heat loss needs to be further optimized in terms of improving energy efficiency. Herein, a two-dimensional solar absorber in which the vertical substrate pumps water to the top surface for sustainable evaporation and reducing heat conduction channels between the evaporation surface and the bulk water is introduced. In addition, the surplus heat of the solar absorber is directly and quickly conducted to a thermoelectric device for electricity generation. This configuration endows the hybrid device with a power density of 1.2 W m −2 at an external resistance of 4 Ω together with an evaporation rate of 4.51 kg m −2 h −1 at 4 suns illumination. Importantly, both the fast response of the hybrid device to the optical concentration and the repeatability of the output current are well supported. Such a hybrid device provides an opportunity to construct an on-site and/or off-network water treatment system with low energy consumption and trade investment.

A Study on Booster Pump System with Flow Sensor for Individual Flow Control Method

Booster pump system (BPS) can control the number of revolutions through an inverter by combining two or more vertical or horizontal centrifugal pumps in a series. Efficiency and energy savings, the most appealing aspects of booster pump systems, can be improved by controlling the operating conditions of individual pumps by measuring the flow rate of each pump. For improved operation, a booster pump system with a flow sensor to detect individual pump flow rates and a control algorithm to manage each low and high flow rate pump’s revolutions per minute are critical. To achieve this, first, the turbine-type flow sensor was developed through computational fluid dynamics and experimentation. The flow sensor was improved using computational fluid dynamics, and its accuracy was validated through experiments. The resulting flow measurement accuracy of the designed flow sensor was within 4%, with a measurement uncertainty of 0.4%. In addition, an experimental pump facility was built and used to evaluate booster pump system performance to investigate the energy saving rate. Then, after driving one low-flow rate pump at a set pressure, the flow and frequency control operation algorithm was used. This algorithm increased the allowed output of the drive pump by increasing the inverter’s frequency. When the frequency corresponding to the allowed output is achieved in the low-flow rate pump rather than the high flow rate pump, power savings increased due to the low-flow rate pump’s extended drive range. The investigations on the developed system’s energy consumption revealed that the energy savings were approximately 6.2% compared to the conventional system, depending on the system in question. The development of a booster pump system with a flow sensor was tested, and it was found to be effective.

Influence of asymmetric inflow on the transient pressure fluctuation characteristics of a vertical mixed-flow pump

In order to investigate the influence of asymmetric inflow on the internal flow fields of a vertical mixed-flow pump, numerical simulation of unsteady flow was carried out under four inflow angles ( θ = 0°, 10°, 20°, and 30°). The reliability of the calculation results was validated through an external characteristic experiment. The fluctuation value of the pressure was defined to obtain the transient pressure fluctuation intensity distribution. Three monitoring points were arranged to compare pressure fluctuation characteristics under different inflow angles. The results suggested that the increase in the inflow angle caused the design operation points to deviate to the over-load flow rate. When the inflow angle increased from 0° to 30°, the axial velocity distribution coefficient and weighted average angle at the inflow runner outlet both decreased. The overall transient pressure fluctuation intensity inside the impeller increased, especially on the pressure side of the blade. Additionally, the transient pressure fluctuation intensity on the pressure side of the guide vane also increased significantly. As a result, the amplitude of pressure fluctuation at the dominant frequency of each monitoring point increased. Relatively speaking, the negative influence of asymmetric inflow on the operational stability of the pumping station was further extended under the part-load flow rate.

Optimization design and unsteady flow analysis of stall characteristics in a vertical centrifugal pump

Abstract In this paper, an optimization design of the vertical centrifugal pump with vaned diffuser was accomplished, and analyzed the internal flow pattern of the model before and after optimization under stall conditions to explore the relationship between design parameters and the stall characteristics. The reasons for the improvement of efficiency and hump characteristics curve after optimization were revealed combined with streamline distributions, entropy production theory and pressure fluctuation. The results show that the error between the external characteristic result calculated by Computational Fluid Dynamics (CFD) and the experimental value is less than 5%, which proves the reliability of the numerical simulation method adopted in this paper. The hydraulic efficiency under multiple operating conditions and stall characteristics of the optimized model have been significantly improved. After optimization, the entropy production rate in the vaned diffuser is greatly reduced, and the improvement of the internal flow pattern in the vaned diffuser is the main reason for slowing down the hump characteristic curve. The hydraulic performance and the stall characteristics of the vertical centrifugal pump can be significantly improved by properly increasing the radial distance of the vaneless region. The matching relationship between the vaned diffuser and the impeller is one of the important factors that affect the stall characteristics. The large-scale vortices in the vaned diffuser is the main reason for the low-frequency pressure fluctuation signal when operating in the hump region. The low-frequency signal in the vaned diffuser of the optimized model is obviously weakened.

Amarinth delivers to oil & gas and nuclear industries

The UK's Amarinth has completed a US$1.5 million order from Armada Madura for six API 610 VS4 vertical pumps for a new floating production storage and offloading unit (FPSO) being built in Singapore for India's Oil and Natural Gas Corporation Limited (ONGC).

Hydraulic Characteristics of Axial Flow Pump Device With Different Guide Vane Inlet Angles

To improve the efficiency of low-head pump device in the large-discharge and low-head domain, the hydraulic characteristics of vertical axial flow pump devices with different guide vane inlet angles were studied using computational fluid dynamics (CFD) and model test methods. The Q∼Hzz and Q∼ηzz curves of the pump device were obtained for different impeller blade angles when the inlet angle adjustments of the guide vane were 0° and −12°. The resulting hydraulic performance was compared and analyzed. The results showed that the pump device efficiency under low-head and large-discharge conditions was improved when the guide vane inlet angle was rotated in the clockwise direction. The reason for the increased pump device efficiency was analyzed using CFD. When the guide vane inlet angle adjustments were 0° and −12° under low-head working conditions, the vortex in the guide vane was eliminated, the hydraulic loss of the guide vane decreased, and the energy performance of the pump improved. When the operational conditions of the pump device deviate from its high-efficiency zone due to limitations in the pump model or the motor itself, the application of these results could improve its hydraulic performance, which is of great significance to the design and application of low-head pump devices.

Study on the flow pattern and pressure fluctuation in a vertical volute centrifugal pump with vaned diffuser under near stall conditions

The vertical volute centrifugal pump is widely used in the long-distance water division project. Flow separation and vortex phenomenon can be observed in the vaned diffuser under near stall operating conditions. This kind of unsteady flow structures would result in the instability of the pump unit which affect the safety and reliability of the unit operation. In this paper, the unsteady flow patterns and induced pressure fluctuation in a vertical volute centrifugal pump with vaned diffuser were simulated based on the SAS turbulence model and refined mesh under near stall conditions. The research results show that the SST turbulence model combined with the selected grid can be validated in the CFD uncertainty analysis during the steady calculation based on the ITTC relevant procedures. The performance results predicted by the SAS turbulence model show quite good agreement with the experimental data, and the prediction errors were less than 5%. The 3D flow matching between the flow angle at the impeller blade outlet and the incidence angle of the guide vane at different spans would induce the stall inception of the pump. The flow patterns of the pump under near stall conditions were revealed combined with vorticity and streamline distributions. When the pump unit was operated under near stall conditions, the main frequency changed from the blade passing frequency 7fn to 0.9fn. It was found that the main frequency was mainly affected by the large-scale vortices in the vaned diffuser, and the main vortices in the vaned diffuser appear at every 0.9 time of the period of one revolution of impeller.

Numerical and Experimental Analysis of Transient Flow Field and Pressure Pulsations of an Axial-Flow Pump Considering the Pump–Pipeline Interaction

The internal flow in a vertical axial-flow pump is a complex unsteady three-dimensional viscous flow. An unstable flow often produces complex flow phenomena such as flow separation, vortices, and secondary reflux, which reduces the operating efficiency of the pump and can endanger safety and stability. In this paper, computational fluid dynamics is used to calculate the flow characteristics in an axial-flow pump using the shear stress transport and curvature correction (SST-CC) model for turbulence modified to account for the rotational curvature. Furthermore, the dependability of the numerical results was confirmed by a test with an actual model of a pump. The transient deviation angle at the impeller inlet of the pump, the stream field attributes in various spanwise parts of the impeller and guide vane, and the velocity distributions at the impeller inlet and outlet were analyzed. The omega method was utilized to recognize the vortex structure inside the guide vane. Moreover, the development of the transient vortex structure inside the guide vane was studied. As the flow rate increased, the scale and turbulent kinetic energy of the vortex structure gradually decreased. The time-domain graph for the impeller inlet is clearly periodic, with three peaks and three troughs in an impeller rotational period. The dominant frequency in the spectrum at each monitoring point was basically the blade frequency, and the secondary dominant frequency was twice the blade frequency.

Numerical analysis of pressure pulsation in vertical submersible axial flow pump device under bidirectional operation

In order to analyze the pressure pulsation characteristics of a single-conduit vertical submersible axial-flow pump device under bidirectional operation, the unsteady numerical simulation of the pump device was carried out based on computational fluid dynamics. The pressure pulsation coefficient and fast Fourier transform were used to analyze the pulsation of each monitoring point in the time–frequency domain. The results show that the pressure pulsation at different positions of the pump device is mainly affected by the impeller rotation, and the amplitude is large at the blade frequency and its harmonic frequency. In the positive operation, the main frequency of pressure pulsation at each monitoring point at the inlet of the impeller is three times the rotating frequency, and in the reverse operation, the main frequency of pressure pulsation at each monitoring point is 0.5 times the rotating frequency. The amplitude of pressure pulsation at each monitoring point at the inlet of the impeller is less than that of the positive operation, while the amplitude of pressure pulsation at the outlet of the impeller and the guide vane is larger than that of the positive operation. In the positive and reverse operation, the axial force of the impeller is significantly affected by the inlet velocity, and the amplitude of the axial force is small in the rotation period. The axial force increases with the increase of flow rate. The radial force of the impeller is significantly affected by the inflow flow pattern. The radial force changes obviously in the rotation period, and the radial force does not change regularly with the flow rate. The radial force of the impeller under reverse operation is 7.75 times that under positive operation.

Conditions for the Occurrence of Resonant Oscillations of Vertical Booster Pumping Units

Features of vibration diagnostics and causes of vibration of vertical booster pump units are considered in the work. On the basis of experimental data and mathematical modeling, the excitation and natural frequencies of vibration characteristic of the pump unit NPV 3600-90-M are determined. It was established that the reverse frequency of the upgraded pump unit in the present case is resonant with its own frequency of the engine-supporting structure system, which is an above-ground part of the equipment under consideration. Taking into account unacceptable limits of ratio of natural and exciting frequencies, optimal range of natural frequency of above-ground part of pump unit is determined.

Voltage Stabilisation of a Drive System Including a Power Transformer and Asynchronous and Synchronous Motors of Susceptible Motion Transmission

A mathematical model is developed of the master circuit of an electric driver system including a power transformer and susceptible motion transmission of asynchronous and synchronous drives. Electric motors drive water pumps by means of motion transmission that comprises two elastic couplings of lumped mechanical parameters and a long shaft of distributed mechanical parameters. Differential equations for oscillatory processes for the long shaft and the elastic couplings are different. The shaft is described with partial derivative Euler–Poisson equations, which, combined with the boundary conditions, form mixed problems from the mathematical point of view. The elastic couplings, on the other hand, are described with the ordinary second type Lagrange equations. Based on the theory of electromagnetic field, the partial differential equations describe the skin effects across the rotor age bars. Vertical pumps are presented by means of a loading torque waveform as a function of the input shaft’s angular velocity. The complex mathematical model serves to analyse electromechanical transient processes across the integrated drive system. Starting from there, conditions of stabilisation of the drive system voltage are determined. Electromechanical state equations are presented in the normal Cauchy form and integrated using the fourth-order Runge–Kutta method. Results of computer simulations are shown with graphics, which are interpreted and described.

An Analytical Model for the Thermal Assessment of a Vertical Double U-Tube Ground-Coupled Heat Pump System in Steady-State Conditions

An analytical model was built to predict the thermal resistance of a vertical double U-tube ground-coupled heat pump that operates under steady-state conditions. It included a geometry obstruction factor for heat transfer throughout the backfill medium due to the presence of the second loop. The verification of the model was achieved by the implementation of five different borehole configurations and a comparison with other correlations in the available literature. The model considered a U-tube spacing range between (2) and (4) times the U-tube outside diameter producing a geometry configuration factor range of (0.29–0.6). The results of the model were utilized for the assessment of the DX ground heat exchanger coupled heat pump system. For similar geometrical configurations, the borehole thermal resistance experienced a decrease as the geometry factor increased. The single U-tube borehole thermal resistance was higher than that of the double U-tube heat exchanger by (10–27)% for the examined geometry configurations. The borehole thermal resistance at tube spacing of twice the tube diameter was higher than the predicted value at the triple diameter and fell in the range of (18–34)%.

Study of the influence of the design of a centrifugal wheel on the pressure characteristics of a multistage pump

The article presents the results of an experimental study of the influence of the number of blades on the pressure-energy characteristics of a multistage centrifugal pump. A vertical submersible multistage centrifugal pump was tested, in which impellers with a different number of blades (6, 7 and 8 blades) were varied. The wheels were manufactured using the latest rapid prototyping technology through SLA printing on high strength polymer resin. The operating speed of the pump was varied at 1450, 2050 and 2850 revolutions per minute (rpm). The effect of different numbers of impeller blades on the performance of a centrifugal pump was investigated on three parameters: pump head (H), hydraulic power and efficiency (η). As a result of the experiments, the dominant influence of the speed on the performance of the centrifugal pump was revealed. It was also found that all pump performance characteristics are generally sensitive to changes in rotational speed, and not to changes in the number of blades. As a result of the research, it was revealed that the flow rate during pump operation plays a key role in head, power and efficiency indicators. The conducted research allowed to conclude that the number of blades does not have a significant impact on the performance of a centrifugal pump.

Justification of vertical split casing pump delivery at withdrawal for basic repair

Justification of vertical split casing pump delivery at withdrawal for basic repair

A study on heating and cooling requirements for green buildings and refugee settlements

In this study, geothermal-based three different systems are examined comparatively and a decision-making method is used to find the best option to use in refugee settlements. Earth air heat exchanger (EAHE), vertical ground source heat pump (VGSHP), and horizontal ground source heat pump (HGSHP) are evaluated from the viewpoint of environmental impact, performance, economy, and health. This study is the first study related to the evaluation of EAHE and GSHP systems by using the analytical hierarchy process (AHP). It is concluded that EAHE is the best option for refugee settlements; also EAHE is a healthier option for the COVID-19 pandemic.

Experimental Study to Analyze Feasibility of a Novel Panelized Ground-Source Thermoelectric System for Building Space Heating and Cooling

A thermoelectric module is a device that converts electrical energy into thermal energy through a mechanism known as the Peltier effect. A Peltier device has hot and cold sides/substrates, and heat can be pumped from the cold side to the hot side under a given voltage. By applying it in buildings and attaching it to building envelope components, such as walls, as a heating and cooling device, the heating and cooling requirements can be met by reversing the voltage applied on these two sides/substrates. In this paper, we describe a novel, panelized, ground source, radiant system design for space heating and cooling in buildings by utilizing the Peltier effect. The system is equipped with water pipes that are attached to one side of the panel and connected with a ground loop to exchange heat between the cold/hot sides of the thermoelectric module and the underground region. The ground loop is inserted in boreholes, similar to those used for a vertical closed-loop Ground Source Heat Pump (GSHP) system, which could be more than a hundred meters deep. Experiments were conducted to evaluate the feasibility of the developed panel system applied in buildings. The results show that: (1) the average cooling Coefficients Of Performance (COP) of the system are low (0.6 or less) even though the ground is used as a heat sink, and thus additional studies are needed to improve it in the future, such as to arrange the thermoelectric modules in cascade and/or develop a new thermoelectric material that has a large Seebeck coefficient; and (2) the developed system using the underground region as the heat source has the potential of meeting heating loads of a building while maintaining at a higher system coefficient of performance (up to ~3.0) for space heating, compared to conventional heating devices, such as furnaces or boilers, especially in a region with mild winters and relatively warm ground.

Analysis of Timing Effect on Flow Field and Pulsation in Vertical Axial Flow Pump

Vertical axial flow pump device has the characteristics of large flow and low head, which is widely used in pumping station projects with head of 3–9 m. In order to study the influence of the timing effect of the impeller relative flow channel and guide vane on the flow field and pulsation in the axial flow pump device, the whole flow channel of the vertical axial flow pump device was taken as the research object. The reliability of the numerical simulation was verified by physical model test. The flow field characteristics and pressure pulsation characteristics of the inlet and outlet regions of the impeller, the guide vane and the campaniform inlet conduit at different timing positions of the impeller under different flow rates were analyzed. The results show that the pressure coefficient distribution of the impeller inlet of the vertical axial flow pump device presents four high-pressure areas and four low-pressure areas with the rotation of the impeller. The pressure pulsation at the inlet and outlet of the impeller is mainly affected by the rotation of the impeller, and the main frequency is 4 times the rotation frequency amplitude of pressure pulsation decreases with the increase of flow rate. When the flow rate increased from 0.8 Qbep to 1.2 Qbep, the average velocity circulation at the guide vane outlet decreased by 12%; there is an obvious negative value region of the internal regularized helicity of the guide vane. When the flow rate increases from 0.8 Qbep to 1.2 Qbep, the amplitude of the pressure pulsation coefficient at the outlet of the guide vane decreases gradually, with a decrease of 94%. When the flow rate is 1.2 Qbep, the main frequency and the secondary frequency of the pressure pulsation are both low-frequency, with obvious low-frequency pulsation characteristics. Under the small flow condition of 0.8 Qbep, the outlet flow fluctuation of seven guide vane was 18.9% on average, and the flow variation of each guide vane was large. Under the optimal flow condition of 1.0 Qbep and large flow condition of 1.2 Qbep, the outlet flow fluctuation of 7 guide vane is 4.7% and 0.56% on average, and the flow change of each guide vane is stable. The outlet flow of the guide vane is mainly concentrated in two guide vane slots of the guide vane, and the flow ratios are 30.56%, 30.14% and 29.16% under three flow conditions, respectively. The research results provide a scientific basis for the optimization design and stable operation of vertical axial flow pump device.

Comprehensive analysis of a vertical ground-source heat pump for residential use in Mexico

Ground-source heat pumps are widely used around the world because of their capacity to provide renewable and emissions-free energy for residential use. A vertical ground-source heat pump in an air conditioner mode is studied experimentally and numerically. The geothermal heat pump is located in Mexico, and consists of a single U-tube of 100 m depth, with 41.16 m3 of conditioned space. A computational fluid dynamics analysis of the geothermal heat exchanger and a thermoeconomic analysis of the heat pump are developed to evaluate the thermal performance of the system under the weather conditions of Mexico, and to know the cost allocation per equipment of the system. Results show that the geothermal heat pump provides a comfort temperature with the minimum value of a comfort relative humidity; the most important temperature changes for the geothermal heat exchanger are present during the first 10 m depth; the system decreases its performance when operating in cities with hot ambient temperatures; the irreversibilities present in the system are small, and the cost of the components depends mainly on the capital investment. In addition, the coefficient of performance of the system is of 3.3–3.6.

Energy, economic and environmental GIS–based analysis of shallow geothermal potential in urban areas—A Spanish case example

During the last decades, both population growth and increasingly concentration in cities turn these areas into major consumers of energy, mainly due to heating and cooling energy demanded by residential and commercial sectors. In parallel, the promotion of renewables and policies aimed to decrease fossil fuel dependence and save emissions have addressed mostly solutions based on renewable energy resources. Under this scenario, this paper evaluates the feasibility of vertical Ground Source Heat Pump systems based on the spatial study of the site–specific parameters affecting their performance at a local scale. A GIS–based energy, economic and environmental multidimensional approach is then proposed to analyze the heating and cooling energy demand by considering the urban pattern and the real space available for the installations. The paper explores and compares different Borehole Heat Exchanger Ground Source Heat Pump systems by using the G.POT method applied to residential customers. Two Spanish residential locations are included as case study. From the results, geothermal resource gives highly beneficial results also for cooling energy demand, which is not usually considered in geothermal analysis. The proposed renewable system can be also evaluated from this multidimensional perspective on both commercial and tertiary sector, as well as in other locations with a diversity of heating and cooling energy demand profiles.