Water Flow Rate Research Articles

Optimization and Regulation Method for Large Blade-regulating Pump Stations Considering Safety Constraints

Abstract In plain areas, making flood control and drought resistance a heavy task. Large water pumping stations undertake the important task of water lifting and scheduling. Due to the physical characteristics of large pumping stations, they are often affected by the upstream and downstream water levels during water lifting scheduling, resulting in low head operating conditions. Low head operating conditions can easily cause pumping stations to operate at excessive power, thereby affecting the health of pumping station equipment. Based on the head efficiency curve of a large blade regulating pump station in this article, by optimizing the regulating mathematical model and considering constraints such as water level, flow rate, power, efficiency, and blade angle adjustment time interval under low head conditions, a dynamic programming calculation method is adopted to construct an optimized regulating method for the pump station. Based on real-time water level, various operating data of the unit are optimized to ensure the blade angle, power, and the flow rate and other parameters are all within the safety constraint range. And various operating data could be used to guiding the real-time optimization and adjustment of the pumping station, and additionally providing the operating foundation for the intelligent pumping station.

Growth and biochemical composition of green seaweed Chaetomorpha linum (O.F. Müller) Kützing (1845) cultured in a range of ionic profiles

Seaweed aquaculture in Inland Saline Water (ISW) can utilise degraded land to produce valuable products. ISW is characterized by its different ionic profile to ocean water (OW), particularly the ratios of sodium (Na+) to potassium (K+) ions, and magnesium (Mg2+) to calcium (Ca2+) ions. The feasibility of seaweed cultivation in varying ionic profiles is not yet well understood. This study investigates the growth of Chaetomorpha linum by length (SL) and biomass (TB), cultured in several ionic profiles by mixture of ISW with OW over two 15-day experiments. The first experiment (EXP 1) investigated growth across a broad range of ionic profiles. C. linum was then cultivated across a more specific range of profiles in the second experiment (EXP 2), based on EXP 1 results. Tanks (50 L) were randomly organised outdoors and salinity was maintained at approximately 25 ppt. SL and TB of seaweed was recorded every 3 days. The proximate and mineral composition of harvested seaweed on Day 15 was also analysed. A significant negative correlation (p < 0.001, r = −0.835, N = 13) was observed between non-discrete TB specific growth rate (SGR) and increasing K+ of media in EXP 1. A significant positive correlation (p < 0.001, r = 0.769, N = 28, EXP 1) was observed between potassium (K) in dry matter (mg.g−1) and K+ in media, suggesting lower K+ in media causes increased TB due to higher water flow rate into cells. Calcium (Ca) content (%d.b.) was much higher in K+ deficient media, indicating Ca accumulation occurs in cells to for ion homeostasis when K is not available. Positive SL SGRs across ionic profiles also indicate this species is capable of a high level of internal ion homeostasis. This study provides context for commercial cultivation of C. linum in varying water types, and presents an avenue for salinity-affected dryland farmers to diversify their income through ISW aquaculture.

Research on the hydraulic response characteristics during the water conveyance process of water diversion projects

Abstract During the initial trial period, the Hanjiang-to-Weihe River Valley Water Diversion Project (HWRVWD) sourced water from the Sanhekou water conservancy junction. It then transferred water through the Qinling water conveyance tunnel and distributed it at the Huangchigou water distribution hub, ultimately transporting it to the Guanzhong area. The hydraulic simulation and real-time control of the water conveyance system play a crucial role in ensuring the safe and efficient operation of this engineering project. To maintain water transfer safety and reasonable scheduling during the water supply process, the hydraulic characteristics of the transient process were calculated and analyzed in this paper. The one-dimension (1D) hydrodynamic mathematical model and advection-dispersion model were established to calculate the hydraulic factors of the 81.78 km Qinling water conveyance tunnel and the Huangchigou water distribution hub within the HWRVWD. Validation results showed that the root mean squared error tended toward zero and the coefficient of determination exceeded 0.97 between the measured values and the simulated values. The opening of gates and upstream inflow directly affected water level variations and storage. Smaller gate openings led to increased water level amplitudes before the gate and faster reaching of maximum water levels, but it also led to opposite trends in flow rates behind the gate compared to upstream water levels. The impact of incoming water flow rates on flow variations at different channel sections was significant. The time for water heads to reach each section and the rate of flow variation positively correlated with incoming water flow rates. Gradual increases in upstream inflow resulted in progressively larger water level amplitudes both before and behind the gate, with an increased maximum value, but more water might be discarded. When the water demand changes, the primary focus is on controlling the upstream inflow, with gate opening adjustments as a secondary measure, to achieve the goal of minimizing or eliminating water wastage.

Design of experimental section of a water tunnel for simulation of heat dissipation condition of seawater-activated battery

Abstract A water tunnel is a crucial experimental apparatus in hydrodynamic research, as the traditional water tunnel has drawbacks such as a small cross-sectional area of the test section and higher costs, which makes it difficult to meet the requirements of a water tunnel for simulating the heat dissipation conditions of the seawater-activated battery. This paper proposes a water tunnel specifically designed for simulating the heat dissipation conditions of seawater-activated batteries, and the water tunnel consists of an external cooling water circulation system and an internal electrolyte circulation system. The experimental section’s design determines the water tunnel’s size and key technical indexes. The temperature distribution contour maps of the experimental section were obtained using Ansys Fluent software simulation. The cooling effect was analyzed, and a cooling water flow rate of 10 m/s was selected. Pressure and velocity contour maps were obtained by simulating the experimental section of the water tunnel. The results show that when the cooling water velocity is 10 m/s, the pressure drop of the experimental section is approximately 1.76 atmospheres. The flow field is uniform and stable, and the heat dissipation power can reach 45.5 kW, meeting the technical requirements.

Energy Consumption Optimization for the Cold Source System of a Hospital in Shanghai-Part I: Analysis of Operating Characteristics and the Control Strategies of the Chillers

Background: Hospitals account for the most proportion of energy consumption in the public building sector. Chillers usually account for most of the overall energy consumption of the cold source system. Objective: To solve the problem of chillers' large energy consumption problem, novel technologies were developed, and achievements were patented. Methods: The operating characteristics influencing factors of the magnetic suspension centrifugal chiller (MSCC) and variable frequency screw chiller (VFSC) of a hospital in Shanghai were analyzed and discussed by actual measurements. Then, based on the operating characteristics of the chiller obtained from the analysis of the measured data, the cooling capacity was classified by the K-Means clustering method to obtain the startup strategy of the chillers. Results: The effects of the supply chilled water temperature, the supply cooling water temperature and variable cooling water flow rate on the maximum cooling capacity and coefficient of performance (COP) of both chillers were explored. The load distribution scheme was discussed based on the chillers' startup strategy. Conclusion: The average part load ratio operation scheme was the preferred chiller distribution scheme. A chiller's maximum allowable part load ratio should not exceed 80% during the low-load operation period and should not be less than 60% during the conventional operation period. It provided a reference for optimizing the chiller operation strategy to reduce system energy consumption.

Design and Performance study of Francis turbine for high head applications.

Abstract Francis Turbines are widely employed globally for their adaptability and operational versatility across a broad range of water flow rates and pressure heads. This study explores the design and optimization of a Francis turbine configured for exceptionally high heads, specifically targeting a design head of 700 m. Traditionally, Pelton turbines are favoured for such high heads, but this study investigates the viability of Francis turbines in this range. Through comprehensive testing, including the development of hill chart diagrams to evaluate performance under various conditions, the study demonstrates promising efficiency levels. Utilizing a simplified approach, the design process involves empirical relations and the Khoj program, resulting in turbine designs representing three different speed numbers: 0.32, 0.42, and 0.52. Efficiency and sediment erosion rates were computed for each and compared between the three designs. The comparison indicates that while the turbine with a speed number of 0.32 exhibits lower efficiency, it offers superior erosion resistivity. Conversely, turbines with speed numbers 0.42 or 0.52 show better efficiency, especially in handling fluctuations in operating conditions. The findings suggest a balance between efficiency and erosion resistivity, recommending the turbine designed for a speed number of 0.32 for superior erosion resistance, and the turbine with a speed number of 0.42 for greater efficiency and operational range. This study broadens the horizon for Francis turbines in high-head applications, offering insights into their potential and viability in extreme conditions.

Experimental research on the heat balance of independent heat extraction-release double helix energy pile

The use of spiral buried pipe of ground source heat pump in civil defense engineering shows great potential, exploring its complex heat transfer features and thermal balance through experimental approaches is essential. This paper utilizes an independent heat extraction-release double helix energy pile to manage condensation heat discharge in underground projects. An experimental platform was established to compare three scenarios: pure heat release, centralized heat extraction, and uniform heat extraction. The pure heat release mode resulted in substantial soil heat accumulation, whereas the centralized heat extraction and uniform heat extraction demonstrated significant reductions in average temperature rise, with decreases of 24.7 % and 31.3 % near the buried pipes, and 27.3 % and 46.3 % in the central regions. The heat-extracting pipe under centralized heat extraction and uniform heat extraction conditions remove 18.7 MJ and 20.3 MJ of accumulated heat, amounting to 10.3 % and 11.2 % of the total heat dissipation, respectively, effectively mitigating the thermal accumulation in the soil during operation. Besides, the outlet temperature of the heat-extracting pipe is predominantly influenced by the highest temperature in the heat exchange zone, lowering the inlet temperature effectively increases the temperature difference between the inlet and outlet, enhancing the amount of heat removed. The accumulation of underground heat can enhance the heat extraction performance of the pipes, and increasing the water flow rate of the heat-releasing pipe positively impacts the heat extraction capacity. After soil temperatures rise, running the heat-extracting pipe with cooler inlet water and a moderately higher flow rate is advised for extracting the accumulated heat.

Experimental study on the thermal performance of a novel vapor chamber manufactured by 3D-printing technology

Vapor chamber holds great application potential in the field of heat dissipation for high-power electronic devices. This study developed a novel vapor chamber using 3D-printing technology to enhance heat dissipation for compact electronic devices. The vapor chamber was constructed from aluminum alloy with a structural dimension of 60×60×30mm3. In this work, the extended condensation structure of the vapor chamber was combined with an external cooling structure, resulting in a 729 % increase in the external heat dissipation area compared to the evaporation area in a limited space. Extensive experiments were conducted using deionized water as the working fluid under various cooling conditions and heat loads. The results showed that the vapor chamber was capable of maintaining a low thermal resistance at high power and high heat flux conditions, with a minimum thermal resistance of 0.087 °C/W when the heat load was 1000 W. At a cooling water flow rate of 0.1 L/s, the vapor chamber demonstrated the capacity to withstand a critical heat load of up to 1600 W, with the heat flux of 326 W/cm2. Compared to conventional vapor chambers, this novel vapor chamber is better able to achieve stable and efficient heat dissipation under high power and high heat flux conditions, especially in a limited space.

Numerical Analysis of Spray Evaporation Process in Desuperheater

Abstract The cooling water is sprayed into the desuperheater to regulate the temperature of the superheated steam. Computational fluid dynamics (CFD) was applied to investigate the spray evaporation process in the desuperheater. Discrete phase model (DPM) was applied to describe the gas-liquid two-phase flow characteristics based on the Eulerian-Lagrangian approach. The Rosin-Rammler distribution and TAB model were used for the description of the primary and secondary droplet breakup, respectively. The coupling effect of gas-liquid two-phase, influence of temperature on latent heat, the stochastic collision and coalescence of droplets were considered in the CFD model. The numerical results show good agreement with the plant data. The hydrodynamics and temperature distribution characteristics were analysed. The influence of water mass flow rate and orifice dimensions on temperature distribution and temperature non-uniformity was further investigated. The results indicate that increasing the water flow rate can improve the desuperheating ability, but it will make the temperature uniformity worse. Under the same operating conditions, smaller orifice diameters are beneficial for production of droplets with smaller size, leading to better desuperheating ability.

Simulation and experimental analysis of fixed and rotating blades on the runner of Oryon Watermill applicable for head drops of the canal

Numerous sites for watermills exist in the world with shallow heads and are possible for power generation either mechanical or electrical. The prime mover required for the energy generation from such sites is in the developing phase with efficient, minimum components, and low cost as a modular unit. The Oryon Watermill (OWM) is one of them developed by Deepwater Energy applicable to water current directly. The working of OWM is used differently on the head drop of the canal with fixed and rotating blades using the NACA 6516 series of airfoil shapes as the novelty of this research. The research covers the CFD simulations with ANSYS Fluent 19.0 of two runners, fabrication, and conduction of tests on-site with a head drop of 1.2 m. The major variable was the water flow rate for both runners with the design discharge of 0.09 m3/s. The analysis of results showed the runner with rotating lamellas performed with 9% and 40% higher efficiency from the simulation and experiment respectively compared to the fixed type. The efficiency achieved from the research is at a low range indicating the availability of large space for future study on performance improvement.

KATANA - water activation facility at JSI TRIGA, Part I: Final design and activity calculations

Water as a primary coolant will play an important role in the performance of fusion reactors, as it causes an ionising radiation field throughout the facility after its irradiation and activation and requires improved shielding for instruments and personnel. To support ITER, the KATANA irradiation facility, which utilises a closed-water activation loop, was built, licenced and commissioned in early 2024 at the TRIGA research reactor at the Jožef Stefan Institute in Slovenia.A comprehensive overview of the KATANA irradiation facility, which serves as a well-defined and stable high-energy γ and neutron source, is given, including the final design, experimental set-up, detector systems and overall timeline. The physical characteristics of KATANA were assessed by analyses of neutron transport simulations leading to activity calculations in connection with a conventional analytical approach, without using CFD calculations. The KATANA facility demonstrated the desired operational characteristics in terms of high and stable water flow rates, leading to high activity values of the observed isotopes 16N, 17N and 19O, which is essential for minimising experimental uncertainties.The preliminary calculations provided in-depth operational knowledge and important data for the KATANA facility, forming a basis for more advanced future experiments.

Thermal request optimization of a smart district heating system

This paper proposes a solution approach to manage the heating plans of tenants served by a district heating plant located in Sweden. To do that, the daily temperature request of each household in the associated pilot region is obtained, and the daily temperature profile of each household is optimized with the help of the proposed decision support system and smart valves. The hot water inflow rates of radiators are remotely controlled via smart valves at each flat to minimize the total energy consumption, carbon emission and cost associated with the energy consumption of the district heating plant. We aim to shave the peak demands while fully satisfying the temperature requests of households without violating their thermal comfort. Peak demand shaving is achieved by generating preheating schedules via mathematical optimization and using the thermal storage potential of the insulated flats. The resulting mathematical optimization model presents significant computational challenges that cannot be efficiently solved using optimization solvers within a reasonable time limit. To this end, we develop three genetic algorithm approaches that are computationally scalable for realistically-sized instances and verified to yield near-optimal solutions for the test instances. Extensive numerical analyses show the effectiveness of the proposed approach and the genetic algorithm since we yield significant carbon emission reduction and cost savings compared with the method that the experts of the utility company propose.

Thermal Performance Solar Flat Plate Collector and Influence of Flow Pipe Design

Flat plate collectors are commonly utilized in both domestic and industrial applications to minimize energy consumption. In this study, solar flat plate collector (SFPC)) with corrugated flow pipe with ten turns placed over flat absorber plate and covered with single glass layer was fabricated and tested, in Al-Mussiab city, Babylon, Iraq (latitude 32.5◦N and longitude 44.3◦E). This research presents the effect flow pipe shape about the SFPC's thermal performance. The designed solar collector utilized employing of 12.5 mm-diameter corrugated copper tubing that extended 19500 mm in total length. According to different rates of water flow namely (50, 100, and 150 L/h). The results indicated that the working fluid's greatest temperature differential between the inlet and outlet of solar collector (12.9°C) at volumetric flow rate (50 L/h). The maximum thermal efficiency (Ƞth) rate of solar flat plate collector was (77%) at (150 L/ h). These results encourage the development of solar collector system and eventually help the sustainable use of solar power in home applications, including solar water heating system.

Parametric Study on Venturi Pressure Drop for Two Phase Oil (D130)-Water Flow for Different Operating Conditions – An Experimental Investigation

The governing parameters which affect pressure drop of two-phase oil-water flow across the venturi meter are water cut and angle of inclination. The study investigates experimentally the effect of inclination and water cut on pressure drop measurements across different venturi meters with beta ratios (β) = 0.4, and 0.6 for oil–water two-phase flow experiments in a 3-inch pipe for different operating conditions. Two-phase inclinable flow loop has been employed for conducting the experiments for different fluid mixture flow rates and water cuts. The working fluids utilized are Exxsol mineral oil (D130) and potable water. The experiments were conducted for water cuts varying from 0 to 100% in steps of 20%, flow rates ranging from 2000 to 12000 barrels per day (BPD), and for horizontal and vertical flow loop inclinations (0◦ and 90◦). Liquid flow rates considered in the study match flow rates of real oil wells. The results indicate that the venturi pressure drop varies linearly with water cuts for both β ratios (0.4 and 0.6). The study indicates that the effect of inclination on venturi pressure drop is not appreciable for all water cuts and flow rates. Also, from the experimental results it can be concluded that venturi with β = 0.6 is favourable for multiphase flow metering (with flow rates ranging from 8000 to 12000 BPD). The tangible findings of the study will be helpful in combating multi-phase flow challenges in oil and petroleum industries.

Enhancement of heat dissipation efficiency in the CSNS target through the innovative design of a serial cooling water channel

This paper presents a coupling of the Monte Carlo method with computational fluid dynamics (CFD) to analyze the flow channel design of an irradiated target through numerical simulations. A novel series flow channel configuration is proposed, which effectively facilitates the removal of heat generated by high-power irradiation from the target without necessitating an increase in the cooling water flow rate. The research assesses the performance of both parallel and serial cooling channels within the target, revealing that, when subjected to equivalent cooling water flow rates, the maximum temperature observed in the target employing the serial channel configuration is lower. This reduction in temperature is ascribed to the accelerated flow of cooling water within the serial channel, which subsequently elevates both the Reynolds number and the Nusselt number, leading to enhanced heat transfer efficiency. Furthermore, the maximum temperature is observed to occur further downstream, thereby circumventing areas of peak heat generation. This phenomenon arises because the cooling water traverses the target plates with the highest internal heat generation at a lower temperature when the flow channels are arranged in series, optimizing the cooling effect on these targets. However, it is crucial to note that the pressure loss associated with the serial structure is two orders of magnitude greater than that of the parallel structure, necessitating increased pump power and imposing stricter requirements on the target container and cooling water pipeline. These findings can serve as a reference for the design of the cooling channels in the target station system, particularly in light of the anticipated increase in beam power during the second phase of the China Spallation Neutron Source (CSNS Ⅱ).

Performance Analysis of Corrugated Twisted Tape Inserts for Heat Transfer Augmentation

This study explores the impact of wavy corrugated twisted tape inserts on enhancing heat transfer and reducing pressure drop in a double pipe heat exchanger. Cu inserts with twist ratios of 3.2, 4.2, and 5.2 were used to create turbulence in the inner tube. Varying water flow rates and measuring bulk mean temperatures at different points revealed significant improvements in heat transfer over smooth tubes. The insert with a 3.2 twist ratio achieved the highest Nusselt number increase (185%) and a 36.33% rise in the friction factor. These results highlight the effectiveness of wavy corrugated twisted tape inserts for optimizing heat transfer, with a 3.2 twist ratio identified as the most effective. Across Reynolds numbers from 4000 to 18000, Nusselt number increases were 77.75% for a 5.2 twist ratio, 167% for a 4.2 twist ratio, and 185% for a 3.2 twist ratio. Friction factors rose by approximately 10.42% for a 5.2 twist ratio, 32.54% for a 4.2 twist ratio, and 36.33% for a 3.2 twist ratio, demonstrating the relationship between twist ratio, heat transfer enhancement.

Cation selectivity during flow electrode capacitive deionization

Efficient separation of specific ions from aqueous media is crucial for advanced water treatment and resource recovery. Flow electrode capacitive deionization (FCDI) offers potential for selective ion removal through continuous operation. This study evaluates the performance of selective cation separation using a commercial activated carbon slurry in a multi-ion solution of monovalent (Li+, Na+, K+) and bivalent (Ca2+, Mg2+) cations. We assess ion removal and cation selectivity under different operational parameters, such as applied potential, slurry flow rate, and feed water flow rate. Our data show that bivalent cations, namely Ca2+ and Mg2+, are preferentially removal due to their higher charge-to-size ratio, aligning with hydrated ion sizes. The highest separation rate was observed for Ca2+ (5.7 μg cm−2 min−1), and the lowest for Li+ (0.2 μg cm−2 min−1). At the highest applied voltage (1.2 V), charge efficiencies reached 70 %, with an energy consumption of 41 Wh mol−1 for nearly complete cation removal. Optimal conditions were identified with a slurry flow rate of 6 mL min−1, feed water flow rate of 2 mL min−1, activated carbon content of 10 mass%, 1 mass% carbon black, and a cell voltage of 1.2 V. These findings highlight the importance of optimizing operational parameters to enhance ion removal.

Development of an Ultrasonic Nebulization System for an Inverse Low Temperature Plasma Ionization Source.

An effective nebulization and evaporation of a liquid sample, like in liquid chromatography, mass spectrometry (LC-MS) couplings, is an essential requirement for the ionization of analyte molecules in the gas phase by, for example, atmospheric pressure chemical ionization (APCI) or the novel low temperature plasma (LTP)-based ion source. These LTP-based ion sources have recently gained interest in the field of atmospheric pressure ion sources, as they can cover a wide range of polarity and molecular mass. They can be used in combination with separation techniques like liquid chromatography or used as an ambient ion source. However, commercial nebulizer systems are of course not constructed to fit to home-built LTP-based ion sources, and this was one incentive to develop a new nebulization system. Instead of an atmospheric pressure chemical ionization (APCI) nebulizer, two commercial nebulizers were disassembled and remodeled to be used as nebulizing systems in an LC-MS setup using an LTP-based ion source. Based on these results, a novel nebulizer system was subsequently developed. To further improve the degree of ionization, cones to focus the LC eluent spray on the plasma region, heating applications, and auxiliary nitrogen gas for dispersion of the solvent droplets were implemented. The LOD that could be calculated via the rule of three resulted in an average of 2.0 μg/L for the APCI-nebulizer and 41 μg/L for the USN. Both could be reduced to 1.4 and 18 μg/L, respectively, by using a TPI-configuration instead of an iLTP. The linearity was equally good for both types of nebulization devices. The final nebulizer could also be operated with a high water content and flow rates higher than those of the two previous ones, indicating an important improvement step.

A Thermodynamic Analysis of a Proton Exchange Membrane Electrolyzer

A thermodynamic, first law analysis was conducted to understand the temperature of a proton exchange membrane electrolyzer when operated at a constant voltage and feed water flow rate. When using the electrolyzer voltage, current, liquid water feed rate and temperature, the electrolyzer operating temperature can be calculated. Heat losses can also be accounted for but are currently neglected. Carpet plots show the resulting electrolyzer temperature under varying conditions. The calculated temperatures are in very good agreement with measurements conducted in our laboratories.

A Thermodynamic Analysis of a Proton Exchange Membrane Electrolyzer

A thermodynamic, first law analysis was conducted to understand the temperature of a proton exchange membrane electrolyzer when operated at a constant voltage and feed water flow rate. When using the electrolyzer voltage, current, liquid water feed rate and temperature, the electrolyzer operating temperature can be calculated. Heat losses can also be accounted for but are currently neglected. Carpet plots show the resulting electrolyzer temperature under varying conditions. The calculated temperatures are in very good agreement with measurements conducted in our laboratories.