Vertical Pump Research Articles

The mathematical model of the drive system with asynchronous motor and vertical pump

The mathematical model of the drive system with asynchronous motor and vertical pump

Evaluation of a transient borehole heat exchanger model in dynamic simulation of a ground source heat pump system

The performance of a vertical ground source heat pump system (GSHPS) largely depends on the fluid temperature leaving the borehole heat exchanger (BHE) that may be affected by the short-term behavior of the BHE. Although considerable research has been carried out to analyze the short-term transient response of the BHEs, few studies have investigated its impact on dynamic simulation of GSHPS. Therefore, this paper presents a numerical approach based on a transient BHE model to evaluate the performance of a residential GSHPS over short and long timescales. The numerical results are compared with the results of EnergyPlus software. It is shown that the proposed model can appropriately predict the dynamic behavior of the system. Moreover, effect of borehole thermal capacity on the performance of the GSHPS is investigated in comparison with a quasi-steady state model. It is found that including the borehole thermal capacity substantially affects the design borehole length. Using the transient model instead of the quasi-steady state model leads to a 16% reduction in the required borehole length.

Экспериментальное исследование рабочего процесса в пилотном образце осевого насоса с трехрядными мультипланными проточными частями

The article describes the stages of preparing the pilot sample of a vertical first-lift condensate pump with a unique axial active part for physical tests and the results from studying the working process in it. The actual parameters of the polyrow hydraulic machine mockup version intended for carrying out physical experiments are given, and the main stages of elaborating the innovative unit’s design are outlined. The working members used in the three-row arrangement are described, their design is shown, and the method for manufacturing the impeller and guide vanes of the proposed complex multirow configuration is considered in detail. Prototyping---an advanced approach practiced in the machinery constructing industry---has been chosen as the method for manufacturing the polyrow pump working members. A technology for manufacturing the active part of a three-row mockup pump on a 3D printer is proposed. Information about the experimental test setup constructed at the research-and-production facilities of the Moscow Power Engineering Institute National Research University Institute is given. The difficulties encountered in designing the experimental test setup and in adjusting its equipment are described together with the methods used to resolve them. The vertical three-row pump assembled at the experimental test setup and prepared for a series of tests according to existing standards is shown. Information on carrying out the physical experiments is briefly outlined. The results from the polyrow pump tests are analyzed. Single-row axial working members designed according to the conventional pattern have been manufactured. The results from tests of the three-row pump and the single-row axial pump have been compared with each other.

Study of Flow Induced Noise in Vertical Inline Pump Using Lighthill Analogy

The pump user demands for specification along with noise and vibration magnitude for extreme operating conditions apart from best efficiency flow. In order to predict the noise level in pumps, the entire unit of pump has to be considered for acoustic evaluation. Hence, the full three dimensional model of vertical inline pump which consists of inlet pipe, impeller, and volute casing is considered for detailing the flow induced noise using Lighthill analogy. The performance characteristics of pump are well matched between experimental and computational results and the overall sound power level at best efficiency flow using computation was compared with empirical relations and found to be agreed well. The streamline patterns along the inlet pipe shows the effects of recirculation and return flow at partload condition and confirm that the utilization of flow passage is not well streamlined even for nominal flow rate. Further, the detailed study of inlet pipe cross sections reveals the nature of different noise sources such as dipole and quadrupole sound levels along with Proudman source power level. The intensity of turbulence and vortices in flow passage is predicted well using quadrupole source and Proudman sound power levels.

Prediction of flow induced vibrations in vertical turbine pumps using one-way fluid-structure interaction

Centrifugal pumps/vertical turbine pumps are important and critical equipment for operation in the power generation, water supply, process industries and petrochemical industries. All centrifugal and vertical turbine pumps have rotors and structures that can vibrate in response to excitation forces. Mechanical and hydraulic unbalance are the two major factors which can create dynamic effects in terms of pump vibrations. In many cases the resulting hydraulic forces due to hydraulic unbalance has much the same effect as the mechanical unbalance. The vibrations in the pumps must be within acceptable limits of applicable standards. If there is higher level of vibrations, it not only leads to operational inefficiencies but also causes pump failures. Hence, it is very important for designers to understand the dominating fact of unbalance force and its origin. The prediction of vibrations in a vertical turbine pump due to the hydro dynamic forces, using numerical methods can help a designer to accomplish a successful design. The interaction between solid and fluid in present case can be completed by one-way coupling method. The one-way fluid-structure interaction approach is presented in present paper to predict the vibrations at specific operating condition which has good correlation with the test data. The advantage of reduced computational effort in this approach can be utilized during initial design stage. In this paper, a case study of one-way FSI approach of a vertical turbine pump is discussed. After detailed explanation about the CFD results, one-way coupling approach is explained with comparison of vibration displacements in both numerical and test data.

Vibration Reduction of Vertical Pumps in Industrial Plants Using Double TMDs

Vibration Reduction of Vertical Pumps in Industrial Plants Using Double TMDs

Numerical Flow Prediction in Inlet Pipe of Vertical Inline Pump

For a pump, the inlet condition of flow determines the outlet conditions of fluid (i.e., energy). As a rule to minimize the losses at the entry of pump, the bends should be avoided as one of the methods. But for the case of vertical inline pump, it is unavoidable in order to save the space for installation. For the purpose of investigation in inlet pipe of vertical inline pump, the unsteady Reynolds-averaged Navier–Stokes equations are solved using the computational fluid dynamics (CFD) code. The results have been shown that there is a good agreement between the performance characteristics obtained from the simulation and experiments. The velocity coefficient from the simulation along the inlet pipe sections is well matched with the theoretical values and found to have variation near the exit of inlet pipe. The pressure and velocity coefficients studies depict the flow physics at each section along with the study of helicity at the exit of inlet pipe to determine the recirculation effects. It is observed that the vortices associated with the motion of the particles are moved toward the surfaces and are more intense than the mean flow. The trends of pressure coefficient at the exit of inlet pipe were addressed with reference to the various flow rates for eight set of radial lines. Hence, this work concludes that for inlet pipe, the generation of circulation was due to the stream path and the reverse flow from the impeller and was reconfirmed with the literature.

CFD Analysis of Double Suction Centrifugal Pump with Double Volute

In this study, Computational Fluid Dynamics (CFD) Analysis is used to investigate the flow in the centrifugal pump impeller using the ANSYS-CFX. Impeller is designed for head of 22 m, discharge of 52.239 m3/hr and for the operating speed of 2970 RPM. Impeller vane profile is generated by tangent arc method and CFD analysis is performed for 1st stage of vertical pump out of 15 stages. Velocity and pressure distribution are analysed for casing and impeller. Using ANSYS-CFX head developed by this impeller is calculated and compared with the required value. From results of CFD analysis, performance curves are plotted and compared with analytical performance curves. Results obtained from CFD nearly matches with analytical results.

Field Tests on Hydrodynamic and Hybrid Operation of a Bidirectional Thrust Bearing of a Pump-Turbine

In vertical shaft pump turbines operating in pumped storage power plants an important role is played by a thrust bearing. Due to the bidirectional character of operation, thrust bearing tilting pads have to be supported symmetrically, which is known to be unfavourable from the point of view of their performance. Large thrust bearings have to be carefully designed so as to minimise excessive thermo-elastic pad deformations. The research into fluid film thrust bearings has been quite extensive over the years, comprising theoretical studies of bearing properties with the use of more and more sophisticated calculation codes. On the other hand, the availability of experimental field data on bearing operation is limited, for obvious reasons. In this paper the authors present part of the results of extensive field tests of a large bearing of a pump-turbine they have conducted in a pumped storage power plant. Hopefully this data will be of interest to other researchers to compare theoretical predictions to measurement data.

Implementation of vertical multistage centrifugal pump system for villages at an altitude of ± 1200m above sea level in Sipahutar – North Sumatera area

Clean water supply is rare in most villages at an altitude of ±1200m above the sea level in North Sumatera due to the topography of the village. The idea to help villagers fulfilling their basic needs in the situation makes this research important. Many experiments had been done previously, such as implementing drilled well but none was successful until we developed a vertical multistage centrifugal pump system. The natural water spring in the area targeted was found in 86 meters depth and would be distributed as far as 500m with area of 1.5km2 from the water tank. The main problem happened was the electric supplies which was always lower than it was expected in that area. Therefore, the successful of the system was happily accepted by the villagers and this research is highly expected to be developed and implemented to other villages, not only in Sipahutar area but also in all Tarutung area.

Heat pump technology: An Alaska case study

Heat pumps are a proven technology around the world and are being increasingly used in Alaska. Technological advances have improved their performance at low temperatures, making them more suitable for arctic environments. This analysis identified data related to 17 heat pumps installed in Alaska, which included air source, ground source, and sea water source systems. The data show that the average installed cost/kW of the heat pumps studied was $5,579. The minimum cost was just over $700/kW for a small air source minisplit system and over $12 000 for a complex vertical loop ground source heat pump. Air source heat pumps in Alaska have operated successfully down to −15 °C. Technological advances are ongoing that should enable further heat pump operation in colder climates.

Nonlinear Analysis and Characteristic Variation of Self-Excited Vibration in the Vertical Rotor System Due to the Flexible Support of the Journal Bearing

Various vibration problems occur in rotating machinery. Specifically, the large amplitude vibration may occur in the vertical pump using a journal bearing. In an actual vertical pump, the stator's structure supporting the pump shaft may be relatively flexible. In such a case, rotor's motion such as amplitude of the self-excited vibration is not able to be predicted accurately without considering the nonlinear fluid film force reacting in the relative motion between the shaft and the flexibly supported bearing stator. However, the vibration characteristics in such situations have not been explained theoretically so far. In this paper, the vibration characteristics of a vertical rotating shaft with journal bearing are investigated. The nonlinear steady-state vibration analysis of the self-excited vibration is demonstrated, and the influences of the parameters, such as fluid viscosity, radial clearance, and stiffness and damping coefficients of the flexible support of bearing stator, on the vibration characteristics of the system are explained. Moreover, these theoretical results of the self-excited vibration in the vertical rotating shaft with journal bearing are verified both numerically and experimentally.

Can brownfield land be reused for ground source heating to alleviate fuel poverty?

Abstract Brownfield land is a legacy of industrial retraction in many towns and cities worldwide, where land remains vacant long after it has gone into disuse, and is often a barrier to redevelopment. Using this land for renewable energy generation is one option that can support development of a low carbon economy and also stimulate regeneration. Fuel poverty is an increasingly pertinent social issue due to rising energy costs. This is particularly true for space heating, accounting for nearly half of all the energy consumed in North European climates. Addressing fuel poverty has become a key consideration in Scotland's internationally leading renewables policy. This article considers how deployment of renewables on brownfield land can be targeted towards addressing heat poverty in social housing. Using Glasgow as a case study, the quantity of available derelict land is calculated, then the spatial association of social housing and urban brownfield land is demonstrated. Technology options for meeting household heat requirements from brownfield land are presented, including scenarios using vertical or horizontal ground source heat pumps. The results suggest that the available urban land could easily supply the needs of all households in fuel poverty, if this scale of investment and non-market intervention was justified.

Production of Nile tilapia Oreochromis niloticus grown in BFT using two aeration systems

Aeration systems used in BFT farming need to meet the dissolved oxygen demand from the biota present in the tank, as well as to keep the particulate matter in suspension. In BFT systems, it is common to use blowers, but the choice of an aerator with better efficiency in oxygen transfer and in electric energy consumption is indispensable. The vertical pump model (VPM) aerator is the most used in intensive tilapia production systems in southern Brazil. The objective of this research was to verify if this aerator model can support Nile tilapia farming under BFT system without producing negative impacts on the functionality neither of the biofloc nor in the production indexes. Simultaneous farming on BFT using blowers served as control. Oreochromis niloticus juveniles with an initial density of 7 kg/m3 were used. After 56 days of farming, the VPM aerator obtained significantly better results, both in water quality parameters and in production indexes, when compared to those obtained in the control treatment. The temperature was higher in the treatment of the blowers due to the lower thermal exchange between the atmospheric air and the tank water. Although the VPM caused lower temperatures, it obtained a productivity of 21.2 kg/m3, compared to 20.2 kg/m3 of the blowers. It was concluded that the use of the VPM aerator had no negative influence on both the formation and functionality of the biofloc, obtaining even higher production rates.

Numerical Investigation of the Three-Dimensional Pressure Distribution in Taylor Couette Flow

An investigation is conducted on the flow in a moderately wide gap between an inner rotating shaft and an outer coaxial fixed tube, with stationary end-walls, by three-dimensional Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD), using the realizable k−ε model. This approach provides three-dimensional spatial distributions of static and dynamic pressures that are not directly measurable in experiment by conventional nonintrusive optics-based techniques. The nonuniform pressure main features on the axial and meridional planes appear to be driven by the radial momentum equilibrium of the flow, which is characterized by axisymmetric Taylor vortices over the Taylor number range 2.35×106≤Ta≤6.47×106. Regularly spaced static and dynamic pressure maxima on the stationary cylinder wall follow the axial stacking of the Taylor vortices and line up with the vortex-induced radial outflow documented in previous work. This new detailed understanding has potential for application to the design of a vertical turbine pump head. Aligning the location where the gauge static pressure (GSP) maximum occurs with the central axis of the delivery pipe could improve the head delivery, the pump mechanical efficiency, the system operation, and control costs.

All-optical tunable microfiber knot resonator with graphene-assisted sandwich structure.

We demonstrate an all-optical tunable microfiber knot resonator (MFKR) by direct light-graphene interaction using external vertical incidence pump laser. The 1530 nm CW pump source is employed to irradiate the sample, which can achieve the performance modulation of MFKR including transmission loss, extinction ratio, and resonant wavelength by the saturable absorption, photo-thermal, and optical Kerr effects, respectively. Compared with the MFKR with only the bottom graphene film, the tunable ranges of transmission loss and extinction ratio are increased by 69 and 125 times, respectively, which can induce a remarkable amplitude tuning. The resonant wavelength of MFKR occurs a red-shift under the irradiation of the pump light, and the red-shift range can exceed one free spectral range (FSR), which means the resonant wavelength could be tuned in the full wavelength range of the transparent window of optical fiber. It is promising for the device to be applied as an all-optical modulator, tunable optical filter, etc.

Damage event analysis of vertical ground source heat pump systems in Germany

In recent years, some spectacular cases of damage occurred with vertical ground source heat pump (GSHP) systems in Germany. Broad media coverage attracted enormous public attention, with reports about land subsidence and ground uplifts causing severe damage to buildings. Consequently, sales of vertical GSHP systems have declined. The current study develops conceptual models illustrating the causes and effects of damage in relation to geological and hydrogeological settings. Our investigations revealed nine cases of serious damage in Germany, causing financial losses of more than 100 million Euros. In most cases, connection of aquifers by leaky annular space grouting was the main cause of damage. Guidelines to regulate the installation of vertical GSHP systems have been introduced successfully in all federal states. However, further risk minimisation strategies must be developed to restore the public’s confidence in GSHP technology. Quality assurance and quality control measures should include in particular the optimisation of backfilling materials and increasing use of monitoring systems.

Hydraulic Fracture Growth in a Layered Formation based on Fracturing Experiments and Discrete Element Modeling

Hydraulic fracture (HF) height containment tends to occur in layered formations, and it significantly influences the entire HF geometry or the stimulated reservoir volume. This study aims to explore the influence of preexisting bedding planes (BPs) on the HF height growth in layered formations. Laboratory fracturing experiments were performed to confirm the occurrence of HF height containment in natural shale that contains multiple weak and high-permeability BPs under triaxial stresses. Numerical simulations were then conducted to further illustrate the manner in which vertical stress, BP permeability, BP density(or spacing), pump rate, and fluid viscosity control HF height growth using a 3D discrete element method-based fracturing model. In this model, the rock matrix was considered transversely isotropic and multiple BPs can be explicitly represented. Experimental and numerical results show that the vertically growing HF tends to be limited by multi-high-permeability BPs, even under higher vertical stress. When the vertically growing HF intersects with the multi-high-permeability BPs, the injection pressure will be sharply reduced. If a low pumping rate or a low-viscosity fluid is used, the excess fracturing fluid leak-off into the BPs obviously decreases the rate of pressure build up, which will then limit the growth of HF. Otherwise, a higher pumping rate and/or a higher viscosity will reduce the leak-off time and fluid volume, but increase the injection pressure to drive the HF to grow and to penetrate through the BPs.

Alternating magnetic field influence on scaling in pump diffusers

This paper examines the influence of alternating magnetic fields on water scale precipitation on diffusers in vertical multistage pumps in real drinking water systems. The exact conditions in pumping stations were simulated in the laboratory using in-house techniques. The testing device consists of two lines, the first a control line and the other for testing, where a permanent magnet was installed. The influence of magnetic fields intensity, post-magnetisation time, temperature and saturation index on calcium carbonate nucleation and crystallisation was studied. The precipitate was analysed using X-ray powder diffraction (XRD) and a scanning electron microscope (SEM). It was found that the precipitate in water from the control line was in the form of calcite, while after the magnet treatment it was in the form of a non-adhesive aragonite powder that could be easily removed with the turbulent flow through the pump diffuser. The results suggest that the magnetic field has a noticeable effect on the transforming process of clusters in the solutions.

OPTIMAL WORKING CONDITIONS OF THE GROUND SOURCE HEAT PUMP FOR HEAT SUPPLY

The method of determination of optimal working conditions of vertical ground heat exchanger for heat pump low temperature water heating system, providing minimum energy cost for heat production is presented in this article. It was determined that there is an optimum speed of a heat carrier to which minimum total cost of electricity for heating system in a whole corresponds when using vertical probes for heat pump heating system. The correlation between the characteristics of vertical ground heat exchanger (depth of the well, the intensity of selection of heat from the soil pipe diameter, the velocity of a heat carrier) in its optimal working conditions was found. It is shown that the optimum velocity of a heat carrier in the lower circuit depends on the depth of the well, the heat exchanger tube diameter, and is almost independent of temperature conditions works of heat pump systems. It is found that the higher velocity observed at the beginning of the heating period in view of energy storage in the ground. Optimum coolant velocity should decrease until the end of the heating season to ensure minimum specific energy expenditure at HPS. Also noted that an optimum velocity increases with increasing depth of the well and with decreasing diameter of the heat exchanger tube. The established correlation may be used when determining the optimum operating conditions of the vertical ground heat pump heat exchanger low-temperature heating systems with a plan to maximize their energy efficiency. Bibl. 8, Fig. 7.