Pump Flow Rate Research Articles

Comparison of the Shutdown Transitions of the Full-Flow Pump and Axial-Flow Pump

In this study, a comparative analysis of the shutdown transitions of a full-flow pump and an axial-flow pump was carried out through numerical simulation and model tests. The UDF method was used to achieve control of the impeller rotational speed during shutdown. The results show that during the shutdown transition, the rate of decline of rotational speed, flow rate, and torque of the axial-flow pump are greater than those of the full-flow pump, so the axial-flow pump stops faster than the full-flow pump. The axial force of the axial-flow pump is significantly lower than that of the full-flow pump, and the maximum value of the radial force of the axial-flow pump is approximately 1.14 times that of the full-flow pump. Due to the influence of the clearance backflow vortex, the impeller inlet and outlet of the full-flow pump generate clearance backflow vortices in the near-wall area, resulting in the overall flow pattern of the impeller chamber being worse than that of the axial-flow pump and the hydraulic loss being greater than that of the axial-flow pump. The runaway speed and flow rate of the axial-flow pump are higher than those of the full-flow pump. Due to the influence of the clearance backflow, the range of the high entropy production rate at the suction side of the impeller of the full-flow pump is always larger than that of the axial-flow pump. The research results in this paper can provide theoretical support for the selection and operation of pumps in large low-head pumping stations.

Comparison between CFD simulation and affinity laws and analysis of the degree of reaction.

Computational Fluid Dynamics (CFD) is a modern technology used to study fluid flow. Experimental methods for predicting the turbomachinery performance involve greater time consumption and financial resources compared to the CFD approach. For the centrifugal pump the impeller is the main component, as it transfers energy to the fluid. The pump flow rate and the total head are directly associated with the impeller rotation speed. The purpose of this paper is to present the analysis and comparison of numerical simulation results using Computational Fluid Dynamics of a centrifugal pump impeller under three different rotation speeds: 3500 rpm (nominal), 3100 rpm and 2700 rpm. The software used was ANSYS-CFX®, the turbulence model adopted was the Shear Stress Transport (SST). Eight operating points were simulated for each rotation. The simulation provided the characteristic curves, pressure distribution, and total and static pressure at the inlet and the outlet of the impeller. The degree of reaction was calculated. The results were compared by application of affinity laws, and showed agreement with them. The results also showed that the degree of reaction increased with increasing flow rate, and it was coherent with the backward curved blade impeller. The simulations show that the energy portions that make up the total energy transferred by the impeller agree with the affinity laws.

Research on renewable energy coupling system based on medium-deep ground temperature attenuation

Medium-deep geothermal has large reserves, a high temperature, a high heat flow density, and other characteristics, but the traditional medium-deep ground heat pump system have long relied on heating from the ground, and soil temperature decreases annually. Using a community building heating system as an example, from a point of view of heat accumulation or not, this article examines the design of a photovoltaic photothermal coupled medium-deep ground source heat pump system (PV/T-GSHP) and a photovoltaic-assisted medium-deep ground source heat pump coupled air source heat pump system (PVGSHP-ASHP). First, the operational performance of a typical GSHP system was compared to that of the PV/T-GSHP and PVGSHP-ASHP systems, both of which were built using TRNSYS. Second, the energy balance and electrical consumption of each system were compared. Finally, the effect of the PV/T-GSHP system’s key parameters and the different ASHP load ratios in the PVGSHP-ASHP system on soil temperature were analyzed. The results showed that after 20 years of operation, the average soil temperature decreased from 38.29 °C to 36.89 °C for the GSHP system, resulting in a decrease in the performance coefficient of the ground source heat pump and the system performance coefficient. The PV/T-GSHP system can address the issue of declining soil temperature with an increase in soil temperature of 0.09 °C. The PVGSHP-ASHP system can mitigate the issue of decreasing soil temperature. The PVGSHP-ASHP system is better than the PV/T-GSHP system in terms of electricity economy. In the PV/T-GSHP system, the larger PV/T component area of similar structures, the smaller flow rate of the heat collector pump, and the volume, inclination, and set temperature of the heat storage tank that are more suitable for the system can achieve higher soil temperatures. As the air-source load ratio increases, the rate at which the soil temperature in the PVGSHP-ASHP system decreases progressively decelerates.

New formulations and experimental validation of non-stationary convolutions for the fast simulation of time-variant flowrates in ground heat exchangers

Flowrate control can have a significant positive impact on the thermal performance and economic profitability of ground-source heat pump systems. Including dynamic advective processes in the design phase, however, remains a challenging task, as few computationally efficient modeling tools allow for their adequate and accurate representation. The present work addresses this issue by presenting new formulations of non-stationary convolutions, an efficient simulation algorithm that relies on the theory of linear time-variant systems for predicting the thermal response of a ground heat exchanger to both dynamic heat loads and flow rates. First, the new original formulations are presented, which include (1) a simple time-domain expression and (2) a fast frequency-domain expression. Then, the efficiency and validity of the new formulations are verified using experimental multi-flowrate thermal response tests involving dynamic circulation, pumping and bleed flow rates in closed-loop and standing column well ground heat exchangers. Results show that the new formulations can reproduce the outlet fluid temperature of both experimental test cases with good accuracy ( MAE = 0.06 ∘ C and 0.26 ∘ C , respectively). At last, the high efficiency of the new frequency-domain expression is demonstrated, with the computing times ( 0.04 s and 0.01 s ) being 100 and 8 times faster than the original formulation in both scenarios.

Blowout-Capping-Fracturing-Relief Well: A Full Cycle Workflow

Summary Failed well-capping attempts following offshore-well blowouts undergoing worst case discharge (WCD) can lead to fluid-driven tensile failures (de facto hydraulic fracture initiations). Subsequent propagation of these fractures may lead to broaching of overburden-rock-formation layers and even the seafloor, providing pathways for reservoir hydrocarbons to escape into the seawater. After capping stack shut-in, the pressure buildup in the fluid column inside the wellbore exposes vulnerable locations to tensile (Mode I) failure. If this shut-in wellbore pressure exceeds the formation breakdown pressure (FBP) in any of the exposed-rock-formation layers, a fracture will initiate and will continue to propagate as long as sufficient energy is provided by the reservoir. Scenarios where the propagating fracture(s) broached the seafloor in the past led to severe environmental impacts, disturbing the local ecology. The quintessential example is Union Oil’s 1969 “A-21 Well” blowout in California’s Santa Barbara Channel, where subsequent well-capping attempts led to multiple broaching instances on the seafloor near the well with thousands of hydrocarbon gallons gushing into the seawater (observable from the sea surface as “oil boilups”). In this paper, numerical modeling is performed on a hypothetical case study using deepwater Gulf of Mexico parameters in order to evaluate the likelihood of a similar scenario by modeling a planar-fracture propagation longitudinally-to-the-wellbore, upon well capping. A workflow is developed that integrates post-blowout WCD flowrate and volume estimations, fracture initiation and propagation modeling following the capping stack shut-in, pertaining to a “cap-and-contain” strategy (including predictions in regard to seafloor broaching), along with relief-well intersection followed by kill-weight-mud injection. The casing-shoe depth is the presumed location of fracture initiation, assuming perfect integrity of all casedhole sections above it. Several sensitivity analyses are performed to investigate the impact of the casing-shoe depth, along with the stiffness of the overburden-rock-formation layer, and the post-blowout-discharge duration on the resultant fracture growth. Finally, the mud density and pump flowrate necessary to compensate the oil column to successfully kill the blown well are quantitatively assessed.

A 3D-printed phantom for quality-controlled reproducibility measurements of arterial spin labeled perfusion.

To develop a portable MR perfusion phantom for quality-controlled assessment and reproducibility of arterial spin labeled (ASL) perfusion measurement. A 3D-printed perfusion phantom was developed that mimics the branching of arterial vessels, capillaries, and a chamber containing cellulose sponge representing tissue characteristics. A peristaltic pump circulated distilled water through the phantom, and was first evaluated at 300, 400, and 500 mL/min. Longitudinal reproducibility of perfusion was performed using 2D pseudo-continuous ASL at 20 post-label delays (PLDs, ranging between 0.2 and 7.8 s at 0.4-s intervals) over a period of 16 weeks, with three repetitions each week. Multi-PLD data were fitted into a general kinetic model for perfusion quantification (f) and arterial transit time (ATT). Intraclass correlation coefficient was used to assess intersession reproducibility. MR perfusion signals acquired in the 3D-printed perfusion phantom agreed well with the experimental conditions, with progressively increasing signal intensities and decreasing ATT for pump flow rates from 300 to 500 mL/min. The perfusion signal at 400 mL/min and the general kinetic model-derived f and ATT maps were similar across all PLDs for both intrasession and intersession reproducibility. Across all 48 experimental time points, the average f was 75.55 ± 3.83 × 10-3 mL/mL/s, the corresponding ATT was 2.10 ± 0.20 s, and the T1 was 1.84 ± 0.102 s. Intraclass correlation coefficient was 0.92 (95% confidence interval 0.83-0.97) for f, 0.96 (0.91-0.99) for ATT, and 0.94 (0.88-0.98) for T1 , demonstrating excellent reproducibility. A simple, portable 3D-printed perfusion phantom with excellent reproducibility of 2D pseudo-continuous ASL measurements was demonstrated that can serve for quality-controlled and reliable measurements of ASL perfusion.

Technical modification of alkali leaching circuit to improve slurry throughput into the autoclave

Tummalapalle Mill represents an alkali leaching-based uranium processing plant. Alkali leaching occurs inside pressurized autoclaves at controlled temperature and pressure. Although the rated capacity of the Tummalapalle Mill is 3000TPD [1], few obstructions were present to achieve the rated capacity. The technical study was done by the process and mechanical engineer team of Tummalapalle Mill for necessary improvements to achieve the rated capacity, which helped in the overall grinding rate of the processing plant. In the alkali leaching section of the Tummalapalle unit, Autoclaves (pressure vessels) are used for alkali leaching purposes. To run the plant at full rated throughput, i.e. 3000TPD, it is required to push the slurry into autoclaves by double hose-diaphragm pumps through spiral heat exchangers with a sufficient flow rate. During the regular course of operation, each double hose-diaphragm pump was able to discharge a limited flow rate with the existing motor-designed parameters. This paper deals with the technical details of double hose-diaphragm pumps, recent technical modifications incorporated & consequent trials taken to increase the pump flow rate and thereby achieve the required throughput into autoclaves.

Smart Manufacturing Implementation of a Continuous Downstream Precipitation and Filtration Process for Antibody Purification

Abstract Recently, continuous bioprocessing has gained momentum in biomanufacturing and can alleviate many of the hurdles faced in batch or semi-batch operations. Moreover, the parallel development of smart manufacturing (SM) allows the rapid small-scale prototyping and large-scale implementation of continuous bioprocesses. With this background, this paper presents the laboratory-scale implementation of a continuous precipitation-filtration process that can ultimately be used for therapeutic protein capture purification. The experimental setup includes four static mixers, four peristaltic pumps, one hollow fiber dewatering filtration module, and multiple pressure sensors and weigh scales. The system also includes an in-line advanced microscopic particle imaging probe that provides real-time images and derived metrics of the precipitate particle morphologies and a fiber optic 880 nm optical absorbance probe. A polyclonal human serum antibody mixture (hIgG) (10 g/L) was used as a stand-in for a monoclonal antibody therapeutic along with 7 % w/v polyethylene glycol (PEG, volume exclusion agent) and 10 mM zinc chloride (cross-linking agent) as the precipitants to demonstrate the principles of operation and control of a precipitation-based process using SM technology. An integrated input/output (I/O) system was used to acquire pressure, flow rate, and weigh scale data and also to communicate with the pumps to change flow rates in real-time. Edge computers communicate with the I/O system and the imaging probe and host the software layer. The software layer enables real-time data acquisition, data-driven and first-principles model predictions, closed-loop control of precipitate particle morphology using pump flow rate of PEG, and cloud communications with the Clean Energy Smart Manufacturing Innovation Institute Smart Manufacturing Innovation Platform. The paper presents the initial results obtained with this integrated system, demonstrating the potential of SM strategies to enhance the production of life-saving biopharmaceutical products.

Cutter Soil Mix-Energywall full-scale test experimental setup

The demand for sustainable heat production is growing worldwide [1]. Classical geothermal borehole installations are costly due to the required boring depth and space demands in the urban environment. Shallow geothermal heat exchangers comprised of thermally-activated geostructures in combination with heat pumps (also known as energy geostructures, EGS) offer an interesting alternative due to a combination of functions [2]. 
 This paper focuses on the thermal properties of the CSM (Cutter-Soil-Mix [3]) Energywall; a novel EGS type in which heat exchanger pipes are installed in a cutter-soil-mix wall to thermally activate it. Therefore, the CSM Energywall serves the dual function of supporting the soil/overlying structure and providing geothermal energy for space heating/cooling. A test site has been setup in Amstelveen, the Netherlands, where this system will be tested for a 1 year period (starting March 2023). A test site picture is shown in Figure 1.The goals of the experiment are to evaluate the thermal efficiency of the system and to assess its thermo-mechanical behaviour by means of numerical models valiated against the data collected from site monitoring. In the first part of the forthcoming paper, test setup and experimental results (both from the field and laboratory tests of the CSM material) will be presented. In the second part, the implementation and validation of the numerical models will be described. Lastly, the paper will focus on the suitability of the CSM-Energywall as a sustainable urban heat source, with particular reference to the Netherlands context.
 The following research questions have been defined for the CSM-Energywall experiments:
 
 What is the heat extraction potential of a CSM-Energywall in sandy and in cohesive soils?
 Does thermal activation affect the mechanical properties of the CSM material?
 What is the long term heat production potential of the CSM-Energywall?
 How accurately can the heat extraction potential be predicted using numerical models?
 
 A test setup at Amstelveen (NL) has been built to answer the above research questions. The test site is located in a building pit of 22 x 13m. CSM-walls were built along the pit perimeter, serving both as a soil retaining structure and as a foundation for the superstructure. The CSM wall has a thickness of 0.55m and is reinforced with IPE steel beams. The bottom of the CSM wall has a level of NAP-18.0m (NAP= Normaal Amsterdamse Peil, vertical reference system of the Netherlands). The bottom of the steel IPE beams is at a level of NAP-15.6m. The ground level at the test site is located at NAP-0.7m and the groundwater table at NAP-1.5m. The building pit has an excavation level of NAP-4.70m. Heat exchanger pipe loops with a diameter of 20mm have been connected to the steel beams representing the CSM wall reinforcement (Figure 1). The loops have a depth of NAP-15.0m or NAP-11.0m. Five main groups of loops are connected to the flow distributer. Each group is then split into six subgroups. Each subgroup consists of two thermoactive steel rebars. The test setup will run for the duration of the building construction. Being able to select the geothermal activation of the shallowest or deepest loops, it will be possible to measure the energy output of both the fine-grained layers (with a bottom depth of NAP-11.0m) and the underlying sandy layers. 
 During the tests the following aspects will be monitored:
 
 Flowrate of fluid through the main loops (FTB4700 Flowmeter)
 Temperature of each main group of loops (PT100 thermowell)
 Flowrate and temperature of heat pump inlet/outlet fluid (Kramstrup Energymeter)
 Temperature of the soil (thermistor strings)
 
 CSM material core samples have been taken for laboratory testing. Cyclic thermal loading, unconfined compression strength (UCS) tests, computerize tomography (CT) scan tests and hot disk tests will be conducted on samples taken from different depths. The goal of the laboratory testing is to evaluate:
 
 The thermal properties of CSM material depending on the original insitu soil composition, needed to assess the thermal efficiency of the system.
 The UCS of the CSM material, and its possible dependency on temperature.
 The macroporisy and density distribution of the CSM material, to gain insight into the material composition.
 The influence of thermal cycling on the material’s mesostructure (e.g. porosity and density distribution).
 
 The full-scale experiment is going to be numerically modelled in 3D using the COMSOL Multiphysics Finite Element software. The model will be validated based on the experimental results of the test after 1 year and calibrated using laboratory measured thermal properties of the CSM material. The model will then be extended to predict the long term efficiency of the CSM- Energywall and its thermo-mechanincal behaviour.

Research of piezoelectric pump with a vortex linear valve structure

In this article, a piezoelectric pump with vortex shaped linear valve structure (PPVSLVS) is proposed on the basis of characteristics of flexible materials. Changes in the working state conversion between “valve-based” and “valve-less” of the PPVSLVS can be realized by adjusting driving conditions. The principle of the working state conversion between “valve-based” and “valve-less” of the PPVSLVS is elaborated for the design of the structure of the PPVSLVS. The prototype of the PPVSLVS and the piezoelectric pump with cardiac valve-like structure is fabricated by 3D printing technique, and the corresponding experiments are also conducted. The experimental results demonstrate that the PPVSLVS is ascribed to be a valve-less piezoelectric pump when the driving voltage is less than 140 V, while the PPVSLVS is ascribed to be a valve-based piezoelectric pump when the driving voltage is above 140 V. When the working state of the PPVSLVS is converted from “valve-less” to “valve-based,” the pump flow rate of this pump will be changed from one peak to double peak. Simultaneously, when the driving voltage of the pump is 180 V at 12 Hz, the pump flow rate reaches a maximum value of 44.3 mL/min. Compared with the piezoelectric pump with a cardiac valve-like structure, under the same driving conditions, the pump flow rate of the PPVSLVS is remarkably increased. When the driving frequency is set as 12 and 24 Hz, the average pump flow rate is improved by 107% and 21.3%, respectively. The distance between the free ends of the valve will affect the working states and flow rate of the PPVSLVS. This study contributes to the application of piezoelectric pumps in artificial hearts.

Analysis of Cavitation Flow Performance in Centrifugal Pump Using OpenFOAM

In order to explore the cavitation mechanism and cavitation cloud development process of centrifugal pump, OpenFOAM7.0 open-source software was used to simulate the unsteady cavitation gas-liquid two-phase flow of IS125 centrifugal pump under different flow conditions. Based on the flow field simulation results, the relationship between the flow rate of the centrifugal pump and the NPSHr was predicted and compared with the experimental data. The comparison showed that it is feasible to use OpenFOAM software to simulate the cavitation flow of centrifugal pump under design condition. Under the design condition, when NPSHa was different, the distribution of cavitation clouds in each blade channel was asymmetric. With the decrease of NPSHa, cavitation clouds continue to develop downstream in the impeller channel and appear on the blade pressure surface. Regardless of whether cavitation occurred in the centrifugal pump, the pressure coefficient showed periodic pulsation, and the pulsation number of the impeller in a rotation cycle was equal to the number of blades of the impeller. The research results can provide an effective open-source software calculation method for centrifugal pump performance prediction.

Analysis of the characteristics of valveless piezoelectric pump with crescent dune bluff body.

To improve the output flow characteristics of the piezoelectric pump in one direction, a new valveless piezoelectric pump with a crescent dune bluff body has been proposed. The pump can achieve low damage to the active substance on the premise that the active cell can guarantee the transport volume. By comparing with the hemispherically deficient and imitated meniscus resistance fluid, the barchan dune resistance fluid which can effectively improve the unidirectional output of the piezoelectric pump is obtained. Combined with the pump theoretical flow calculation formula, these influencing parameters, the degree of inclination, the sand ridge radius and the order of the crescent dune were analyzed. Finally, an experimental prototype of a valveless piezoelectric pump has been fabricated by 3D printing technology, and the pump flow test is being conducted. The relationship between frequency, voltage and output flow has been obtained. The test results show that with a dune inclination of 37.5, a sand ridge radius of 6.75 mm and a dune order of 4, the flow rate of the piezoelectric pump is best at 194.7 mL/min. The experimental results agree with the simulation results, showing the effectiveness of the valveless piezoelectric pump structure.

Evaluation of a new magnetically suspended centrifugal neonatal pump in healthy animals using a veno-venous extracorporeal membrane oxygenation configuration.

The objective of this animal study was to evaluate the hemodynamic performance of a new centrifugal pump for extra-corporeal membrane oxygenation (ECMO) support in neonates. Six healthy swines were supported with veno-venous ECMO with the New Born ECMOLife centrifugal pump (Eurosets, Medolla, Italy) at different flow rates: 0.25, 0.5, 0.6, and 0.8L/min; three animals were evaluated at low-flows (0.25 and 0.5L/min) and three at high-flows (0.6 and 0.8L/min). Each flow was maintained for 4hours. Blood samples were collected at different time-points. Hematological and biochemical parameters and ECMO parameters [flow, revolutions per minute (RPM), drainage pressure, and the oxygenator pressure drop] were evaluated. The increase of the pump flow from 0.25 to 0.5L/min or from 0.6 to 0.8 L/min required significantly higher RPM and produced significantly higher pump pressures [from 0.25 to 0.5L/min: 1470 (1253-1569) versus 2652 (2589-2750) RPM and 40 (26-57) versus 125 (113-139) mmHg, respectively; p < .0001 for both - from 0.60 to 0.8L/min: 1950 (1901-2271) versus 2428 (2400-2518) RPM and 66 (62-86) versus 106 (101-113) mmHg, respectively; p < .0001 for both]. Median drainage pressure significantly decreased from -18 (-22; -16) mmHg to -55 (-63; -48) mmHg when the pump flow was increased from 0.25 to 0.5L/min (p < .0001). When pump flow increased from 0.6 to 0.8L/min, drainage pressure decreased from -32 (-39; -24) mmHg to -50 (-52; -43) mmHg, (p < .0001). Compared to pre-ECMO values, the median levels of lactate dehydrogenase, d-dimer, hematocrit, and platelet count decreased after ECMO start at all flow rates, probably due to hemodilution. Plasma-free hemoglobin, instead, showed a modest increase compared to pre-ECMO values during all experiments at different pump flow rates. However, these changes were not clinically relevant. In this animal study, the "New Born ECMOLife" centrifugal pump showed good hemodynamic performance. Long-term studies are needed to evaluate biocompatibility of this new ECMO pump.

ON THE ISSUE OF TRANSPORTATION OF LIQUEFIED CARBON DIOXIDE

Link for citation: Vanchugov I.M., Rezanov K.S., Shestakov R.A. On the issue of transportation of liquefied carbon dioxide. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 190-209. In Rus. The relevance of the study is caused by the need to capture and utilize one of the main types of greenhouse gases – carbon dioxide (CO2). This need is primarily related to the ever-increasing CO2 emissions, three quarters of which are accounted for by the combustion of various fuels. The main aim is to analyze and systematize international methods for calculating the pipeline transport of liquefied carbon dioxide (LCO2) to determine differences in numerical results, including factors taken into account and not taken into account in the methods under consideration, as well as to analyze water transport type as an alternative to pipeline transport. Objects: liquefied carbon dioxide, a pipeline for transporting LCO2. Methods: numerical modeling of LCO2 pipeline transport according to international methods to estimate the required diameter capable of providing a given pumping flow rate, analysis of the results obtained. Results. The authors have carried out a review of existing methods for calculating LCO2 pipelines, carried out numerical modeling and analysis of the results were, during which it was revealed that most models ignore the influence of impurities, which, however, affect the technological parameters of operation and modeling of LCO2 pipelines, which will lead to inaccuracies in their design and operation. In addition, it was found that the fluid velocity in the pipeline is calculated according to the parameters in the initial section, which corresponds to its minimum value in the pipeline, and is assumed to be equal to it throughout the pipeline without taking into account the expansion of LCO2 from changes in temperature and pressure along its length and, consequently, without taking into account additional pressure losses and changes in other technological parameters that they can directly affect the operational safety and economic efficiency of the designed or operated LCO2 pipeline. It should also be noted that the diameter determination equations depending on the length of the pipeline are not suitable for estimating the optimal diameter of the pipeline. As for alternatives to pipeline transport, first of all, it is worth noting the possibility of transportation by tankers over long distances or the possibility of using LCO2 to increase the flow rate of deposits on the shelf and in hard-to-reach places of the coastal zone.

Effect of Instantaneous Starting Pump on Fluid Transient Flow in Managed Pressure Cementing

Abstract The fluctuating pressure generated by the instantaneous starting pump of cementing operation might easily cause formation fracture in narrow safety window formations. Accurate transient fluctuating pressure calculation and dynamically managed backpressure are required to achieve precise control of wellbore pressure in managed pressure cementing. Considering the transient flow characteristics of cementing fluids in the wellbore, unsteady transient friction, and the variation of high pressure-high temperature (HTHP) cementing fluid properties, a transient flow mathematical model of instantaneous starting pump during managed pressure cementing is established, and the method of characteristics is used for solution. Based on tht established model analyzes the magnitude and variation of wellbore pressure under different model factors, temperature conditions, pump start duration, and target pump flowrate, which can achieve more accurate analysis of transient flow. The pressure and flow fluctuations generated during the instantaneous starting pump of cementing are significant, and the dynamically managed wellhead backpressure can effectively control the wellbore pressure in the safe pressure window formations. This can reduce the risk of well leakage and provide reliable technical support for safe operations of instantaneous starting pumps during managed pressure cementing.

Reliability and performance evaluation of a solar PV-powered underground water pumping system

The operation and effectiveness of a solar-powered underground water pumping system are affected by many environmental and technical factors. The impact of these factors must be investigated to be considered when developing these systems and to ensure their dependability. This study evaluated the dependability and performance of photovoltaic water pumping system (PVWPS) under real operating conditions by examining the effects of solar irradiance, panels’ temperature, and components' efficiency. From December 2020 to June 2021, experiments were conducted on a 10 hp PVWPS located in Bani Salamah, Al-Qanater-Giza Governorate, Egypt, at latitude 30.3° N, longitude 30.8° E, and 19 m above sea level. The irradiance values reached 755.7, 792.7, and 805.7 W/m2 at 12:00 p.m. in December, March, and June, respectively. Furthermore, the irradiance has a significant impact on the pump flow rate, as the amount of pumped water during the day reached 129, 164.1, and 181.8 m3/day, respectively. The panels' temperatures rose to 35.7 °C, 39.9 °C, and 44 °C, respectively. It was observed that when the temperature rises by 1 degree Celsius, efficiency falls by 0.48%. The average efficiency of photovoltaic solar panels reached its highest value in March (13.8%) and its lowest value in December (13%).

Experimental investigation of fresh and time-dependent rheological properties of 3D-printed cementitious material

Unlike traditional construction processes, three-dimensional cementitious material printing requires more accurate control of the pumping flow rate. To this end, the predictability of the rheological properties of fresh cementitious mixtures and the property change over time are critical for the fabrication process. In this paper, the fresh rheological properties of twenty different mixtures were measured in the large gap viscometer, and three non-Newtonian fluid models (Bingham model, modified Bingham model, and Herschel-Bulkley) were applied to predict the dynamic yield stress and plastic viscosity of each material. The applicability of these models was assessed, and their relative deviation was quantified and discussed. Using the well-established Bingham model, the temporal evolution of the dynamic yield stress and plastic viscosity of the material was then characterized. Based on the measured and predicted rheological properties, an open loop control method was then implemented to harmonize the flow volume per unit length during printing processes to improve the printing quality and buildability of the material.

Effect of montmorillonite and humic acid on cotransport of g-C3N4 and lead: The role of triazine ring in lead adsorption and deposition in soil components

In the past few years, Graphitic carbon nitride (g-C3N4) has been produced on a large scale and has been widely used because of its excellent optical properties and physicochemical stability. It is easy to ignore the risk of g-C3N4 transport in the environment, including soil and groundwater, due to the non-toxicity of metals. Based on this situation, we investigated the effects of pumping flow rate, ionic strength, and the presence of lead (Pb) on the transport behavior of g-C3N4 in quartz sand, montmorillonite, and humic acid-coated sand through column experiments. The retention of g-C3N4 in the media and the adsorption mechanism of Pb onto g-C3N4 were analyzed by FTIR and XPS. The results showed that fast flow rate and low ionic strength were favorable conditions for the transport of g-C3N4. The cotransport experiment results showed that Pb reduced the outflow of g-C3N4 by more than 50%. Contrarily, 6.95%, 0.43%, and 11.01% Pb were hindered in quartz sand, montmorillonite, and humic acid-coated sand due to the presence of g-C3N4. Compared with the uncontaminated media, the recoveries of g-C3N4 in Pb contaminated quartz sand, montmorillonite, and humic acid-coated sand were reduced by 0.34%, 5.86%, and 15.34%, respectively. Concomitantly, which were attributed to the special triazine ring structure and the abundant bonding modes with soil components and Pb, g-C3N4 particles were easier to deposit in montmorillonite and humic acid-coated sand, and could be used as the carrier to release 6.70% and 5.64% Pb from contaminated quartz sand and humic acid-coated sand.

Numerical simulation of cascaded absorption-two-stage 4-bed adsorption cooling cycles for efficient low-grade heat utilization

Thermal-driven sorption cooling technology was developed to address some pressing challenges including high energy consumption, rising fuel prices, and environmental issues associated with traditional electrical-driven cycles. Nevertheless, this technology needs to be improved in terms of thermal performance and energy efficiency. This study investigates the performance of new cascade single-effect absorption (ABC) and two-stage four-bed adsorption (4ADC) cooling systems powered by low-grade heat source temperatures. Four different configurations are proposed to make proper use of low-temperature heat sources between 45 and 70 °C and improve heat recovery. The use of this temperature range to drive conventional ABC is still considerably lacking in the literature. The ABC does not typically operate below 60 °C. Additionally, the effects of operating conditions on performance are also investigated. The simulation models for both ABC and 4ADC systems are experimentally validated separately and showed excellent agreement. Results showed that the maximum cooling capacity obtained from the proposed system ranges between (5.4–17.1) kW with COP of 0.46–0.47. The COP is found to be relatively insensitive to regeneration temperatures. Increasing the solution pump flow rate increases the system performance by about 25% over the ranges of the regeneration temperature. The proposed configurations provide high energy performance compared with previous related studies. The obtained results proved that the proposed cascade configurations can recover the available low-grade heat source and operate effectively with temperatures between 45 and 70 °C.

Models and Interpretation Methods for Single-Hole Flowmeter Experiments

Subsurface and groundwater flow characterization is of great importance for various environmental applications, such as the dispersion of contaminants and their remediation. For single-hole flowmeter measurements, key characteristics, such as wellbore storage, skin factor heterogeneities, and variable pumping and aquifer flow rates, have a strong impact on the system characterization, whereas they are not fully considered in existing models and interpretation methods. In this study, we develop a new semi-analytical solution that considers all these characteristics in a physics-based consistent manner. We also present two new interpretation methods, the Double Flowmeter Test with Transient Flow rate (DFTTF) and the Transient Flow rate Flowmeter Test (TFFT), for interpreting data collected during single and multiple pumping tests, respectively. These solution and methods are used as follows. (i) The impact of wellbore storage, transient pumping rate, and property heterogeneities on the interpretation of data collected during single pumping tests are studied over 49 two-aquifer cases. (ii) The effect of the skin factor heterogeneity on transmissivity and storativity estimates, as well as the variability range of the (non-unique) corresponding solutions, are analyzed for the interpretation of multiple-pumping experiments. The results presented in this work show the importance of the various properties and processes that are considered, and the need for the new models and methods that are provided.