Type Of Pump Research Articles

ASSESSMENT AND TECHNICAL CONSTRAINT IDENTIFICATION OF SMALLHOLDER IRRIGATION PUMP IN ARSI AND EAST SHEWA ZONE, OROMIA

Efficient irrigation begins with properly installed and maintained pumps, motors, and engines. For this, the study was conducted on potential irrigation pump users of the Arsi and East Shewa zones with the objective of identifying the technical constraints of smallholder irrigation pump users. Doddota from Arsi and Dugda and Bora woreda from the East Shewa zone were selected. 211 samples size from 2321 pump users were used for data collection. The constraints listed by respondents, like pump damage, pump cost, long priming, and fuel, were the most common bottlenecks in pump irrigation schemes. Pump damage was positively correlation with use of un-recommended suction and delivery head, age of pump, long priming time and continues operation time but negatively correlation with pump maintenance, experience in irrigation farming and educational level of the household. Long priming and fuel consumption was positively (+Ve) correlation with use of un-recommended suction and delivery head, age of pump, operation time and pump size. From the existing pump type respondent responses, KAMA pumps were highly available on the market, vulnerable to damage, and had sufficient spare parts with values of 60.66, 64.45 and 44.08%, respectively. The lowest were Cushion their values were 1.42%, 3.32% and 3.78%, respectively. The respondents also reply, due to absence of governmental pump maintaining organization, cost of maintenance at local and private garage were very expensive (68.25%) and expensive (26.07%). This makes another problem on small holder irrigation pump. Therefore, it is recommended to government to add pump maintaining structure at engineering center which serves' closely to scheme users and providing regular training on maintenance checklist. It is also recommended for engineering and socio-economic researchers to conduct research collaboratively to assess the gap frequently for other kebele pump user and technical performance evaluation for pump that have problems.

Analysis of double suction pumps in both pump and turbine modes using entropy factor

Pump as turbine (PAT) is one of the most extensively applied hydraulic machinery and play a prominent role in converting mechanical energy into electricity. However, choosing the suitable type of pump to use as a turbine is always a problem. Therefore, it is necessary to carry out a detailed analysis of these two operating modes. In this paper, a double suction pump is numerically simulated based on SST k- ω model in CFX. The hydraulic performance and internal flow are studied with different flow rates. The simulation results verified by experiments show that the flow rate at the best efficiency point of the turbine is approximately 1.7 times that of the pump, and the head is 2.22 times that of the pump. Besides energy loss is analyzed based on entropy production theory and the specific location of the energy loss of each domain is studied in detail. Analysis of entropy production proves that flow energy dissipation primarily concentrates within the volute casing in pump mode, with an average proportion of 45.6 %. While in the PAT mode, it is mainly concentrated in the impeller and suction chamber, accounting for 56 % and 25.2 % respectively.

High-Order Topological Pumping on a Superconducting Quantum Processor.

High-order topological phases of matter refer to the systems of n-dimensional bulk with the topology of m-th order, exhibiting (n-m)-dimensional boundary modes and can be characterized by topological pumping. Here, we experimentally demonstrate two types of second-order topological pumps, forming four 0-dimensional corner localized states on a 4×4 square lattice array of 16 superconducting qubits. The initial ground state of the system at half-filling, as a product of four identical entangled 4-qubit states, is prepared using an adiabatic scheme. During the pumping procedure, we adiabatically modulate the superlattice Bose-Hubbard Hamiltonian by precisely controlling both the hopping strengths and on-site potentials. At the half pumping period, the system evolves to a corner-localized state in a quadrupole configuration. The robustness of the second-order topological pump is also investigated by introducing different on-site disorder. Our Letter studies the topological properties of high-order topological phases from the dynamical transport picture using superconducting qubits, which would inspire further research on high-order topological phases.

Performance investigation of a high-temperature absorption-compression heat transformer with liquid refrigerant injection

The high-temperature heat pump technology is a promising approach to utilizing low-temperature waste heat while meeting industrial demands for high-temperature heat. However, existing high-temperature heat pump systems face challenges including insufficient temperature lift, system complexity, and rapid performance degradation at high output temperature. This paper proposes a novel, structurally simple high-temperature absorption-compression heat transformer, aiming to recover heat below 100 °C and achieve a large temperature lift above 70 °C. The system is analyzed from the aspects of energy, exergy, key parameters that impact its performance, and techno-economic comparison. Results show that injecting liquid refrigerant into the compressor chamber mitigates high superheat effects on the compressor, allowing for higher absorption pressure. The system achieves an output temperature of around 170 °C, with the compressor outlet temperature below 120 °C. Moreover, some liquid refrigerant evaporates by absorbing compressor superheat. This reduces power consumption of the compressor, heat input of the evaporator, and overall system exergy loss. Thus, the proposed system demonstrates improvements of 6.5 % and 7.5 % in coefficient of performance and exergy coefficient of performance, respectively. Besides, it is feasible to achieve absorption temperatures exceeding 170 °C by increasing the solution concentration or the pressure ratio, with the former being the more cost-effective approach. Furthermore, the specific costs of the proposed system are more than 20 % lower than those of other types of high-temperature heat pumps, demonstrating its superior economic feasibility.

Pump-driven clinical infusions: laboratory comparison of pump types, fluid composition and flow rates on model drug delivery applying a new quantitative tool, the pharmacokinetic coefficient of short-term variation (PK-CV)

Pump-driven clinical infusions: laboratory comparison of pump types, fluid composition and flow rates on model drug delivery applying a new quantitative tool, the pharmacokinetic coefficient of short-term variation (PK-CV)

Comparison of the Energy Contributions of Different Types of Ground Heat Exchangers Related to Cost in a Working Ground Source Heat Pump System

Geothermal systems face adoption challenges due to their high initial investment cost. Accurate cost analyses and a more precise understanding of updated prices could assist geothermal industry projects in obtaining investment financing and better money management with the right equipment. As the cost of geothermal installations can vary widely depending on case and location, it seems essential to clarify the factors and parameters that determine the cost of the system. These include the type of loop system, the ground conditions, the type of heat pump, the system size, and the geographical location. The scope of this study is to compare the operation of various types of ground heat exchangers (GHEs) present in a Ground Source Heat Pump (GSHP) system installed in the coastal area of the Mediterranean climate zone of Cyprus. The highlight of this work is that it presents real installation cost data as well as recorded total energy contributed by the GHEs to the GSHP system of a HP cooling and heating capacities of 101 kW and 117 kW, respectively. The input contribution from the GHEs to the HP is 85,650 kWh (308,340 MJ) in summer and 25,880 kWh (93,168 MJ) in winter. It is shown that, among the three groups of GHEs investigated, the open-well GHE complex has the lowest cost per kWh ratio (0.32 EUR/kWh), followed by the vertical GHE complex (1.05 EUR/kWh), and lastly by the helical coil GHE (2.77 EUR/kWh). This clearly suggests that when underground water is available, the open-well GHE is much more favorable than other GHE types.

Prevalence of qacEΔ1, qacE, oqxA, oqxB, acrA, cepA and zitB genes among multidrug-resistant Klebsiella pneumoniae isolated in a cardiac hospital

Background. Infections caused by multidrug-resistant (MDR) Klebsiella pneumoniae are the leading cause of mortality worldwide. The widespread use of disinfectants and antiseptics has caused the emergence of K. pneumoniae with reduced sensitivity to them, which, in combination with MDR, can pose a significant epidemiological threat. The aim of the study was to assess the prevalence of efflux pump and transporter genes associated with biocide resistance and their association with antibiotic resistance among K. pneumoniae isolated in a cardiac surgical hospital. Materials and methods. K. pneumoniae isolates (n = 50) from the patients and medical equipment were tested by polymerase chain reaction for the presence of genes of 4 types of efflux pumps (qacEΔ1, qacE, oqxA, oqxB, acrA) and 2 transporters involved in the outflow of cations (cepA) and zinc ions (zitB). Spearman's rank correlation test was used to assess the strength of the association between the efflux pumps, beta-lactamase genes and mobile genetic elements. Results. The occurrence of K. pneumoniae containing qacEΔ1, qacE, oqxA, oqxB, acrA, cepA and zitB was high: 54, 62, 100, 84, 100, 72 и 96% respectively. K. pneumoniae with a combination of all the studied pumps was most often detected (32%), and these isolates were MDR in 100% of cases. The qacE, qacEΔ1 genes were closely associated with resistance to cephalosporins, carbapenems, fluoroquinolones, carbapenemase genes, and integrons. The results of the study showed that the genes of various efflux pumps associated with biocide resistance and their combinations were widely represented among the clinical isolates of MDR K. pneumoniae. Conclusion. The high prevalence of efflux pump genes associated with resistance to quaternary ammonium compounds, chlorhexidine and zinc salts and their significant association with antibiotic resistance in nosocomial K. pneumoniae underlines the importance of further studying the mechanisms of cross-resistance to biocides to improve methods of combating MDR nosocomial pathogens.

Performance and Economic Analysis of Two Types of High-Temperature Heat Pump Based on New Refrigerants

This paper proposes, for the first time, the research concept of comparing energy and economy between transcritical cycle high-temperature heat pumps and subcritical cycle high-temperature heat pumps with new refrigerants. Experiments and simulations are conducted to compare the system performance and economy of two heat pumps, and the effects of different factors on the performance of two heat pumps are analyzed. The results show that R744/R1234yf (90/10) and R515-1 are the preferred refrigerants for transcritical cycle heat pumps and subcritical cycle heat pumps, respectively. The COP of the R744/R1234yf (90/10) transcritical heat pump is generally higher than that of the R515B-1 subcritical heat pump, and compared to the R515B-1 subcritical heat pump, the cost recovery period of the R744/R1234yf (90/10) transcritical heat pump is about 9–15 years. Therefore, it is recommended that users who use heat pumps for a long time choose transcritical cycle heat pumps. Meanwhile, with the change of evaporation temperature, the system COP of the R515B-1 subcritical heat pump and R744/R1234yf (90/10) transcritical heat pump increases by 61.11% and 65.91%, respectively. In addition, the optimal charge amount for the R515B-1 subcritical heat pump is 81.8% of that of the R744/R1234yf (90/10) transcritical heat pump.

Test Procedures and Mechanical Properties of Three-Dimensional Printable Concrete Enclosing Different Mix Proportions: A Review and Bibliometric Analysis

Three-dimensional printable concrete (3DPC) has become increasingly popular in the building and architecture industries due to its low cost and fast design. Currently, there is great interest in the mix design methods and mechanical properties of 3DPC, particularly in relation to yield stress analysis. The ability to extrude and build 3D-printed objects can be significantly affected by factors such as the rate of extrusion, nozzle size, and type of pumps used. It has been observed that a yield stress lower than 1.5 to 2.5 kPa is not sufficient to maintain the shape stability of concrete, while a yield stress above this range can limit the material’s extrudability. Furthermore, the strength properties of 3DPC are influenced by factors such as changes in yield stress and superplasticiser dosages. To meet the high mechanical strength and durability requirements of 3DPC in the construction industry, it is essential to analyse the material’s early-age mechanical properties. However, the development of standardised test methods for 3DPC is still deficient. To address this issue, a bibliometric analysis was conducted to comprehensively review the diverse test methods and mechanical characteristics of 3DPC with different mix proportions. To produce high-performance concrete from various additives and waste materials, it is critical to have a basic understanding of the hydration processes of 3DPC. Moreover, a detailed analysis of the environmental impact and energy efficiency of 3DPC is necessary for its widespread implementation. This review article will highlight the recent trends, upcoming challenges, and benefits of using 3DPC. It serves as a taxonomy to navigate the field of 3DPC towards sustainable development.

Comparison of Advanced Multivariable Control Techniques for Axial-Piston Pump

This article is devoted to a comparison of two advanced control techniques applied to the same plant. The plant is a certain type of axial-piston pump. A linear-quadratic (LQR) controller and an H-infinity (H∞) controller were synthesized to regulate the displacement volume of the pump. The classical solution to such a problem is to use a hydro-mechanical controller (by pressure, flow rate, or power) but, in the available sources, there are solutions that implement proportional-integral-derivative (PID), LQR, model predictive control (MPC), etc. Unlike a classical solution, in our case, the hydro-mechanical controller is replaced by an electro-hydraulic proportional valve, which receives a reference signal from an industrial microcontroller. It is used as the actuator of the pump swash plate. The pump swash plate swivel angle determines the displacement volume, respectively, and the flow rate of the pump. The microcontroller is capable of embedding various control algorithms with different structures and complexities. The developed LQR and H∞ controllers are compared in the simulation and real experiment conditions. For this purpose, the authors have developed a laboratory experimental test bench, enabling a real-time function of the control system via USB/CAN communication. Both controllers are compared under different pump loading modes. Also, this paper contributes an uncertain model of an axial-piston pump with proportional valve control that is obtained from experimental data. Based on this model, the robust stability of the closed-loop system is investigated by comparing the structure of a singular value (μ). The investigations show that both control systems achieved robust stability. Moreover, they can tolerate up to four times larger uncertainties than modeled ones. The system with the H∞ controller attenuates approximately at least 30 times the disturbances with frequency up to 1 rad/s while the system with the LQR controller attenuates at least 10 times the same disturbances.

Optimization of rotor profile design and analysis of transient flow fields in an asymmetric singular double claw vacuum pump

The claw vacuum pump is widely used in vacuum industries due to its high-performance, compact structure, and oil-free operation. This study delves into the rotor profile and internal flow field characteristics of an asymmetric singular double claw vacuum pump. Theoretical profile equations for the male-female rotor of claw vacuum pumps were given, and a three-dimensional transient simulation of the internal flow field was carried out using the dynamic mesh reconstruction method. The simulation result was also verified by experiments. Analysis shows that: the radial clearance significantly affects the volumetric efficiency of the claw vacuum pump, with a larger effect than the axial clearance; the maximum instantaneous temperature corresponds to radial clearance, leading to maximum thermal deformation concentrated at the claw tip; thermal deformation is the predominant factor contributing to maximum deformation; the smaller the coefficient of thermal expansion, the less the rotor material affects the claw vacuum pump clearance. Based on these insights, we have innovatively optimized two elements of the theoretical claw vacuum pump rotor profile, i.e., the curvature of the cusp B and three optimized configurations of the complex EH section. The optimization results provide a solid theoretical basis for advancing the design and practical application of this pump type.

Domain adversarial transfer fault diagnosis method of an axial piston pump based on a multi-scale attention mechanism

Effective failure diagnosis of axial piston pumps is crucial to guaranteeing the security and steady run of hydraulic equipment systems. However, the current domain-adaptive methods have insufficient feature extraction and domain-adaptive capability for axial piston pumps across conditions and some unlabeled sample conditions. Therefore, this paper proposes a method of domain adversarial transfer fault diagnosis based on multi-scale attention mechanisms. The method enhances the ability of the model to adapt to the differences in various fault information by constructing a multi-scale residual feature extraction network. The domain adaptive capability of the network is improved by constructing a joint loss function to decrease the distributional discrepancies between the source and the target domain data. The experimental consequences demonstrate that the method can differentiate various fault types of axial piston pumps across conditions and can achieve a high fault identification rate without labeled samples in the target domain.

Study on the influence of the blade inlet area-to-impeller inlet area ratio on hydraulic performance under various specific speed conditions

Abstract To investigate the unknown effects of the relationship between the impeller inlet area and blade design on the hydraulic performance of centrifugal pumps at various specific speeds within typical rotating fluid equipment, this paper aims to conduct experiments on three types of pumps with different specific speeds (ns =155, ns =125, and ns =88). The study analyzes how the S1/S0 ratio, which represents the blade inlet area to impeller inlet area ratio, affects the hydraulic performance of different centrifugal impellers. Furthermore, it explores the changing patterns of how the S1/S0 ratio influences the pump’s head and efficiency. The results indicate a recommended range of S1/S0 ratios for centrifugal pumps optimized for efficiency at different speeds. When considering the impact on cavitation performance, it is suggested that the S1/S0 ratio should not exceed the upper limit of this recommended range.

Hydrogen extraction from 0.1 % H2–He mixture: The interplay phenomena of electrode, temperature, and voltage in BZYN & BZCYYb

Hydrogen pumps, crafted from proton-conductive ceramic electrolyte and paired with either oxide or metallic electrodes, have been designed for the extraction of hydrogen isotopes from helium gas mixtures containing 0.1 % hydrogen isotopes, particularly within the context of TES for nuclear fusion reactors. This study presents the electrochemical hydrogen permeation research conducted on the perovskite proton conductor materials BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) and BaZr0.8Y0.16Ni0.04O3-δ (BZYN) under these operational conditions. It was observed that nickel electrodes provided superior performance over SrFe0.8Mo0.2O3-δ (SFM) electrodes in terms of hydrogen extraction efficiency. Hydrogen pumps that integrated BZCYYb as the electrolyte with nickel electrodes showed enhanced efficiency, while those utilizing BZYN as the electrolyte coupled with nickel electrodes demonstrated greater stability. Furthermore, the study explored the voltammetric nonlinearity at low hydrogen concentrations and the dependency of concentration polarization efficiency on both voltage and temperature, aiming to establish optimal conditions that balance stability and efficiency for both types of hydrogen pumps.

Patient Satisfaction Survey on Portable Infusion Pumps for Colorectal Cancer Chemotherapy: Hard-Shelled or Soft-Shelled?

Elastomeric infusion pumps are widely used in colorectal cancer chemotherapy. However, no studies to date have investigated patient preferences regarding different infusion pump types. Twenty patients with unresectable colorectal cancer undergoing chemotherapy were initially treated with a portable hard-shelled continuous infusion pump, followed by a soft-shelled continuous infusion pump. The respondents used a numerical rating scale (0-10) to rate their comfort when using each pump, their ease of carrying it, the pump size and shape, its weight, their ease of reading its memory, and their overall satisfaction with it. They were then asked to determine which pump they would ultimately prefer. In terms of comfort, significantly higher user satisfaction was reported for the soft-shelled pump during the daytime and when going out (P < 0.001, P < 0.001, respectively). For pump portability, size, shape, and weight, the soft-shelled type also outperformed the hard-shelled one (P < 0.001, P=0.0011, P < 0.001, respectively). However, the hard-shelled pump scored significantly better in terms of ease of viewing memory (P < 0.001). Overall satisfaction was significantly higher for the soft-shelled pump than the hard-shelled type (P=0.0095). Finally, 13 patients (65%) indicated that they would prefer a soft-shelled pump for their next treatment, while only one patient (5%) preferred a hard-shelled alternative. A preference for soft-shelled pump was observed, particularly in female patients and those with a body mass index of < 22 kg/m2. The selection of portable elastomeric infusion pumps should consider the preferences of patients with colorectal cancer, as these devices have the potential to enhance their quality of life.

Performance evaluation of a modified axial flow water Lifting pump for small to medium irrigation in Nigeria.

Most irrigation pumps used in Nigeria are imported. Consequently, the challenges farmers faced in using these pumps include but not limited to the following; priming before operation, relatively low-capacity delivery at low head and high price which is often time not affordable by peasant farmers. The objective of this research was to develop an axial flow pump with locally sourced materials and affordable by farmers for small to medium scale irrigation in Nigeria. The design of the pump for the study was adopted from an existing and functioning axial pumping machine, developed by Agricultural Machinery and Mechatronics Department, Kasetsart University, Thailand. The pump was fabricated at the workshop of National Centre for Agricultural Mechanization (NCAM), Ilorin, Nigeria. Diesel fuel was used in powering the pump because of higher torque deliverable. The developed pump based on its capacity can be used to irrigate one hectare in one hour at 16.2 mm depth of water using 2000 rpm at 1m head and 9.6 mm depth of water using 1000 rpm at 3 m head. The maximum water discharge of 162 m3/h (45 l/s) was at 1m using a speed of 2000 rpm with water to fuel delivery of 124.29 l/s. The maximum water discharge of 162 m3/h (45 l/s) was at 1m using a speed of 2000 rpm with water to fuel delivery of 119.57m3/L. And the least water discharge of 59.30 m3/h (28 l/s) and water delivery per fuel was 41.0m3/L at 3 m head at 1000 rpm. Therefore, the developed pump operates best at lower head of 1m featuring a 3kW prime mover. The developed pump based on its capacity can be used to irrigate one hectare in one hour at 16.2 mm depth of water using 2000rpm at 1m head and 9.6 mm depth of water using 1000rpm at 3m head at a moisture content of 45% on a sand-loamy soil. Statistical analysis reveals relationships between pump speed, head, fuel consumption, and various performance indicators. The centrifugal pumps were found to produce lower discharge than axial flow pumps at different water heads evaluated. Comparative economic analysis demonstrates the pump's superiority over conventional centrifugal pumps in terms of water-fuel delivery efficiency and operational cost. This study introduced a locally modified axial flow pump as a practical, cost-effective, and efficient solution to irrigation challenges faced by small and medium-scale farmers in Nigeria. This pump has higher capacity delivery, spare parts are readily available at local market, it is appropriate for use where the irrigation head requirements are low and large volumes of water is required to be lifted at low pressure, it is appropriate where water can be lifted from rivers and canals and then directed to farmers' fields for irrigation. It is also applicable in rice farm flooding and flood drainage. This type of pump is good for flood (surface) irrigation system, which include furrow, border, basin irrigation and uncontrolled flooding in loamy and clay soils for rice production and sugarcane productions. The pump's adoption and economic viability positions it as a potential catalyst for increased food production, income, and food security in the country.

Disinfectant polyhexamethylene guanidine triggered simultaneous efflux pump antibiotic- and metal-resistance genes propagation during sludge anaerobic digestion

The environmental transmission of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) exerted devastating threats to global public health, and their interactions with other emerging contaminants (ECs) have raised increasing concern. This study investigated that the abundances of ARGs and MRGs with the predominant type of efflux pump were simultaneously increased (8.4–59.1%) by disinfectant polyhexamethylene guanidine (PHMG) during waste activated sludge (WAS) anaerobic digestion. The aggregation of the same microorganisms (i.e., Hymenobacter and Comamonas) and different host bacteria (i.e., Azoarcus and Thauera) were occurred upon exposure to PHMG, thereby increasing the co-selection and propagation of MRGs and ARGs by vertical gene transfer. Moreover, PHMG enhanced the process of horizontal gene transfer (HGT), facilitating their co-transmission by the same mobile genetic elements (20.2–223.7%). Additionally, PHMG up-regulated the expression of critical genes (i.e., glnB, trpG and gspM) associated with the HGT of ARGs and MRGs (i.e., two-component regulatory system and quorum sensing) and exocytosis system (i.e., bacterial secretion system). Structural equation model analysis further verified that the key driver for the simultaneous enrichment of ARGs and MRGs under PHMG stress was microbial community structure. The study gives new insights into the aggravated environmental risks and mechanisms of ECs in sludge digestion system, providing guidance for subsequent regulation and control of ECs.

Analysis Of Battery LiFePO4 Pack Capacity As An Alternative Energy Source In Water Pump Shimizu PS-135 E

Electrical energy is a basic need for society and is a fairly economical resource that can be used for various activities. Human activities are supported by electrical energy. Electrical energy has important role in supporting all activities such as the industrial, commercial building, transportation and housing sectors. Water pump Shimizu PS-135 E is a type of water pump that is widely used in family activities, its function is to supply water from water sources (reservoirs, wells) for family needs such as bathing and washing. The pump relies continuously use of electrical energy, it means that, if this energy source runs out, the pump will not be able to operate automatically and ultimately. For this reason, in this research, the LiFePO4 type battery is used as an alternative energy source to overcome the above problems. The results of the analysis in this research show that to run the water pump for 1.5 hours a 42,000 mAh 12 Volt LiFePO4 battery is required which is arranged in a 4S - 7P manner and as a battery protector a 60 A Daly type BMS is used. Testing the load on the water pump until the battery cut time showed that the battery drain time was 1.3 hours, the battery condition was 20% with a voltage of 12.89 Volts. AC output voltage 230.4 Volts, current 1.145 A, power (P) = 195 Watts, Power Factor 0.72. The volume of water produced in 1.3 hours (78 minutes) is 2,182 liters.

Deformation investigation of electromagnetic diaphragm pump rubber diaphragm.

A diaphragm pump is a type of volumetric pump that has excellent sealing performance. An electromagnetic diaphragm pump is a kind of widely adopted diaphragm pump that has a simple structure, low power loss, and high cost performance. However, the calculation method of deformation for the electromagnetic diaphragm pump rubber diaphragm is presently lacking. Herein, a calculating method of deformation for the electromagnetic diaphragm pump rubber diaphragm is proposed. By establishing and analyzing a deformation model of the electromagnetic diaphragm pump rubber diaphragm, a theoretical relationship between the deformation of the electromagnetic diaphragm pump rubber diaphragm, the size of the electromagnetic diaphragm pump rubber diaphragm and the pressure of fluid is determined. The experimental results indicate that the biggest difference between the tested axial deformation and the calculated axial deformation of the electromagnetic diaphragm pump rubber diaphragm is 0.04 mm and the calculation results show agreement with the experimental results.

A Study on the Transient Characteristics of the Power-Off Transition Process of a Double-Volute Centrifugal Pump

A double-volute centrifugal pump is a very important pump type; the internal flow field of a centrifugal pump will change drastically during the transition process of power failure, which will affect the safety and stability of the pump’s operation. In this paper, the CFD numerical simulation method is used, and the UDF procedure is developed to realize the continuous update of the impeller speed at each time step. The working parameters, such as the torque and flow rate at the instantaneous moment, are obtained through the sequential iteration of each small step, and a numerical simulation of the power-off transient is carried out on a double-volute centrifugal pump; additionally, the changes in the external characteristic parameters and the internal flow field of the centrifugal pump are analyzed in detail. The results show that the double-volute centrifugal pump experienced four different modes after power failure, namely pump mode, braking mode, turbine mode, and runaway mode, and the absolute values of the runaway speed and runaway flow rate are 1.465 times and 1.21 times the initial values, respectively. Through the analysis of the flow field in different regions, the change processes of the generation, development, and disappearance of the vortex at each position of the centrifugal pump are obtained, and the change and development processes of the internal velocity gradient of the centrifugal pump are obtained. In addition, it is found that the high-speed area located in the second volute runner is larger than that of the first volute runner because the second volute runner is shorter and narrower than the first volute runner.