Research on the Matching Characteristics of the Impellers and Guide Vanes of Seawater Desalination Pumps with High Capacity and Pressure

This paper presents the matching characteristics of impellers and guide vanes of high capacity and pressure seawater desalination pumps by using computational fluid dynamics (CFD). The single-stage pump is numerically calculated, and its external characteristics are consistent with the test results of model pump. Taking this scheme as a prototype, the research is carried out from three aspects: (i) the impeller blade outlet width; (ii) the number of impeller and guide vane blades; and (iii) the area ratio of impeller outlet to guide vane inlet. The results indicate that the blade outlet width significantly affects the pump head and efficiency. Appropriately increasing the number of guide vane blades or changing the number of impeller blades can improve efficiency and expand the high-efficiency area. Additionally, increasing the throat area of the guide vane has the opposite effect on the large flow and small flow area of the pump. An optimized hydraulic model design scheme is obtained.

Effect of Blade Thickness on Internal Flow and Performance of a Plastic Centrifugal Pump

Blade thickness is an essential parameter of the impeller, which has significant effects on the pump performance. The plastic pump generally adopts thick blade due to low strength of plastic. The effects of blade thickness on the internal flow and performance of a plastic centrifugal pump were discussed based on the numerical methods. Two kinds of blade profile, the constant thickness blade (CTB) and the variable thickness blade (VTB), were investigated. The results indicated that, for the CTB, when the blade thickness was less than 6 mm, the pump performance did not change significantly. When the blade thickness exceeded 6 mm, the pump head and efficiency decreased rapidly. The pump head and efficiency of CTB 10 decreased by 42.2% and 30% compared with CTB 4, respectively. For the VTB, with blade thickness in a certain range (6 mm–14 mm), the pump performance changed slightly with the increased of trailing edge thickness. The minimum blade thickness of the plastic centrifugal pump should be 4 mm based on the finite element analysis. A variable thickness blade (VTB 4-8-4) with the maximum thickness located at 60% chord length was proposed to improve the pump performance, and its efficiency was 1.67% higher than that of the CTB 4 impeller.

Experimental Investigation of Oil/Water Emulsion Rheology in Electric Submersible Pump and its Effect on the Pump Head Performance

The presence of formation water throughout the oil well production lifetime is inevitable and consequently forming the dispersion or the emulsion due to the immiscibility of those two phases and the strong shear force acting in a rotating ESP. The formation of stable emulsion close to the inversion point will significantly increase the effective viscosity of an emulsion. This paper will present an experimental investigation of emulsion rheology inside the ESP and its effect on ESP performance under various oil viscosities and different water cuts (WC). Multi stages radial type ESP were assembled into a viscous flow loop which was initially developed by Zhang (2017). Emulsions at each WC formed from different oil viscosities, similar oil density, and surface tension. Multistage ESP was used to circulate oil/water emulsions in a close flow loop. Mass flowmeter measures both mass flow rate and fluid density, and the effective emulsion viscosity derived from an in-line pipe viscometer (PV) which locates downstream of the ESP discharge. The pressure transmitter is occupied in each pump stage to measure the pressure increment. The experiment results present in terms of pump boosting pressure at each water cut and the flow rate delivered by the pump. A Single-phase oil experiment was run at a different temperature to validate the accuracy of the PV. The data discrepancy of PV's viscosity and rotational viscometer is ±6%. The experiment results captured the emulsion's effective viscosity trend as a function of WC. A significant increase of effective viscosity close to the inversion point was observed, and it occurs due to a higher number of water droplets and hydrogen bonds which lead to an increase in hydrodynamic forces thus generating a tight emulsion. The experiment results reveal that a higher oil viscosity 70 cp reaches an inversion point at 30% - 35% WC. Meanwhile, for lower oil viscosity 45 cp reaches the inversion point at 35% - 40% WC since the turbulence increases with the decrease of oil viscosity. The increasing of effective viscosity in the water-oil emulsion induces higher pressure loss in the pump due to high friction loss, and it deteriorates the pump head. Nevertheless, as the WC increases further, the pump head will advance close to the single-phase water performance since the water turns as the continuous phase. Eventually, we can observe a prudent relationship in the pump performance in the change of emulsions effective viscosity as a function of WC. The inversion point phenomena occur at a different range of WC for different oil viscosity. Therefore, it is vital to set the possible range of operational conditions away from the inversion point. A better understanding of these aforementioned issues will lead to an accurate ESP design for optimum well performance.

Analysis, Design and Validation of a Vaned Diffuser for Improved Fish Friendliness

The primary cause of mechanical-related fish injury and mortality in turbomachinery is blade strike. Fish contained in the flow may strike with the rotor blades and the fixed diffuser vanes, the latter being a non-negligible factor causing fish damage in pump system. In this study, an experiment-based correlation of fish mutilation ratio acts as critical strike velocity. The relation between strike damage in a vaned diffuser and the theoretical pump head is presented as a function of specific speed. As an example, a vaned diffuser is designed for a single-bladed, mixed-flow impeller with the purpose of improving fish friendliness. This pump can be scaled to operate with a head up to 14 m at peak efficiency, without fish damage in the diffuser. Subsequently, experiments are conducted to show the retained pump performance as well as the great improvement of fish friendliness.

Safety and Efficacy of a Novel Centrifugal Pump and Driving Devices of the OASSIST ECMO System: A Preclinical Evaluation in the Ovine Model

Background: Extracorporeal membrane oxygenation (ECMO) provides cardiopulmonary support for critically ill patients. Portable ECMO devices can be applied in both in-hospital and out-of-hospital emergency conditions. We evaluated the safety and biocompatibility of a novel centrifugal pump and ECMO device of the OASSIST ECMO System (Jiangsu STMed Technologies Co., Suzhou, China) in a 168-h ovine ECMO model.Methods: The portable OASSIST ECMO system consists of the control console, the pump drive, and the disposable centrifugal pump. Ten healthy sheep were used to evaluate the OASSIST ECMO system. Five were supported on veno-venous ECMO and five on veno-arterial ECMO, each for 168 h. The systemic anticoagulation was achieved by continuous heparin infusion to maintain the activated clotting time (ACT) between 220 and 250 s. The rotary speed was set at 3,200–3,500 rpm. The ECMO configurations and ACT were recorded every 6 hours (h). The free hemoglobin (fHb), complete blood count, and coagulation action test were monitored, at the 6th h and every 24 h after the initiation of the ECMO. The dissection of the pump head and oxygenator were conducted to explore thrombosis.Results: Ten sheep successfully completed the study duration without device-related accidents. The pumps ran stably, and the ECMO flow ranged from 1.6 ± 0.1 to 2.0 ± 0.11 L/min in the V-V group, and from 1.8 ± 0.1 to 2.4 ± 0.14 L/min in the V-A group. The anticoagulation was well-performed. The ACT was maintained at 239.78 ± 36.31 s, no major bleeding or thrombosis was observed during the ECMO run or in the autopsy. 3/5 in the V-A group and 4/5 in the V-V group developed small thrombus in the bearing pedestal. No obvious thrombus formed in the oxygenator was observed. The hemolytic blood damage was not significant. The average fHb was 0.17 ± 0.12 g/L. Considering hemodilution, the hemoglobin, white blood cell, and platelets didn't reduce during the ECMO runs.Conclusions: The OASSIST ECMO system shows satisfactory safety and biocompatibility for the 168-h preclinical evaluation in the ovine model. The OASSIST ECMO system is promising to be applied in clinical conditions in the future.

Optimization of the centrifugal slurry pump through the splitter blades position

Optimal transfer of two-phase solid-liquid flow (slurry flow) has long been a major industrial challenge. Slurry pumps are among the most common types of centrifugal pumps used to deal with this transfer issue. The approach of improving slurry pumps and consequently increasing the efficiency of a flow transmission system requires overcoming the effects of slurry flow such as the reduction in head, efficiency, and wear. This study attempts to investigate the changes in the pump head by modifying the slip factor distribution in the impeller channel. For this purpose, the effect of splitter blades on slip factor distribution to improve the pump head was investigated using numerical simulation tools and validated based on experimental test data. Next, an optimization process was used to determine the characteristics of the splitter (i.e., length, number, and environmental position of the splitter) based on a combination of experimental design methods, surface response, and genetic algorithm. The optimization results indicate that the splitters were in a relative circumferential position of 67.2% to the suction surface of the main blade. Also, the optimal number and length of splitter blades were 6 and 62.8% of the length of the main blades, respectively. Because of adding splitter blades and the reduction in the flow passage, the best efficiency point (BEP) of the slurry pump moved toward lower flow rates. The result of splitter optimization was the increase in pump head from 29.7 m to 31.7 m and the upkeep of efficiency in the initial values.

Re-design the use of PV to distribute water from tanks to rural area for Mentawai especially in Central Siberut sub-district

The redesign of the water pump stuck in the district of Central Siberut is reused by using the Solar Panel as an alternative energy source. The materials and tools used are Booster pump, pipe, air valve, wash out, blow off and gate valve. The booster pump is used to pump high pressure water from the tank so that it can reach Saibi village, where Saibi village is the farthest village compared to Simulaklak village, where the distance from the tank to Simulaklak village is only 1.5 km and the tank to Saibi village is 4.5 km the elevation difference between the tank and the village of Saibi is 25 meters above sea level. The total water demand in Simulaklak and Saibi villages is 17.63 liters / second with flow rates in Simulaklak and Saibi villages of 2.25 m / sec and 1.69 m / sec, for the pump head obtained from the tank to Simulaklak village is 72,1 m and the pump head from the tank to Saibi Village is 120.31 m. The standard atmospheric pressure obtained for Simulaklak village is 10,284 mH2O and for Saibi village is 10.301 mH2O. Booster pump is an alternative that can be used for distributing water from the tank to the village.

Energy Loss and Radial Force Variation Caused by Impeller Trimming in a Double-Suction Centrifugal Pump

Impeller trimming is an economical method for broadening the range of application of a given pump, but it can destroy operational stability and efficiency. In this study, entropy production theory was utilized to analyze the variation of energy loss caused by impeller trimming based on computational fluid dynamics. Experiments and numerical simulations were conducted to investigate the energy loss and fluid-induced radial forces. The pump’s performance seriously deteriorated after impeller trimming, especially under overload conditions. Energy loss in the volute decreased after trimming under part-load conditions but increased under overload conditions, and this phenomenon made the pump head unable to be accurately predicted by empirical equations. With the help of entropy production theory, high-energy dissipation regions were mainly located in the volute discharge diffuser under overload conditions because of the flow separation and the mixing of the main flow and the stalled fluid. The increased incidence angle at the volute’s tongue after impeller trimming resulted in more serious flow separation and higher energy loss. Furthermore, the radial forces and their fluctuation amplitudes decreased under all the investigated conditions. The horizontal components of the radial forces in all cases were much higher than the vertical components.

Investigating external and internal working processes of mining machines when operating on “unclarified” water in underground conditions

Introduction. The article considers the issues of mine drainage study, including the working processes of the centrifugal pumps pumping “unclarified” water in arduous underground conditions. Such problems resolution is of high practical and scientific importance. Methods of research. Scientific and practical experience in the field of mine drainage was analyzed and generalized. The centrifugal pump modes were considered and promising research tasks in this field were outlined. Thus, the continuous income of groundwater to mine workings requires the uninterrupted operation of pumps. One of the most common types of mine-drainage plants is a multistage centrifugal pump which fulfills its functions to the full if properly operated. However, “unclarified” water pumping requires a new technique for centrifugal pump optimal modes determination in such service conditions. Result and analysis. The study of hydraulic, volumetric, and mechanical efficiency dependency on pump modes, the analysis of working processes within centrifugal pumps when operating on “unclarified” water, and the procedure and calculation of TsNS (multistage centrifugal pump) head-capacity curve were presented in the paper to justify the effectiveness of the presented solutions and conclusions. Scope of results. It is recommended that the research results are introduced in all enterprises conducting underground mining operations with the mine drainage.

63 The “Brighton Connector”: A Simple, Reproducible and Cost-Effective Technique for Bilateral Antegrade Cerebral Perfusion During Aortic Arch Surgery

Aim Surgery of the aortic arch presents significant technical and physiological challenges. Selective antegrade cerebral perfusion (SACP) during arch surgery has been shown to improve mortality and neurological outcomes in these patients. At our centre, we aimed to develop a safe, reliable, and cost-effective technique to provide bilateral antegrade cerebral perfusion without the need of another pump head. Method We developed our system using equipment that is included in the accessory packaging for the Sorin Xtra cell saver system, which is readily available in cardiac surgical units nationwide, but often discarded as it is not required. An EOPA arterial return cannula and the TRUE FLOW RDB SACP cannula were joined using our novel connection. Results A single surgeon has used the “Brighton Connector” for 6 patients in the last two years. All patients made a satisfactory recovery with a 0% rate of mortality or permanent neurological deficit. Conclusions All components in our circuit are already approved for use in cardiac theatres, and the connection tubing would normally be discarded, making our method cost neutral. We demonstrate through a case series that mortality and neurological outcomes are good and comparable with other techniques.