Water Level In Tank Research Articles

Feasibility test of the concept of long-term passive cooling system of emergency cooldown tank

When a passive cooling system is activated in the accident of a nuclear reactor, the water in the emergency cooldown tank of that system will eventually be fully depleted by evaporation. If, however, the evaporating water could be returned to the tank through an air-cooled condensing heat exchanger mounted on top of the tank, the passive cooling system could provide cooling for an extended period. This feasibility of new concept of long-term passive cooling with an emergency cooldown tank was tested by performing an energy balance test with a scaled-down experimental setup. As a result, it was determined that a naturally circulating steam flow can be used to refill the tank. For an air-cooled heat exchanger, the cooling capacity and air-side natural convective heat transfer coefficient were obtained to be 37% of the heat load and between 9 and 10.2W/m2/K depending on the heat load, respectively. Moreover, it was clearly verified that the water level in the emergency cooldown tank could be maintained over the long-term operation of the passive cooling system.

Water Distribution System Modeling and Optimization: A Case Study

In the last years, the scientific literature has reported an increasing use of hydraulic models to describe water distribution systems (WDS). Hydraulic models represent tools for managing the complexity of WDSs, and a number of optimization methods have been proposed to improve the performance of these infrastructures. However, because of the lack of available data on WDSs many works have only considered synthetic WDS with idealized behaviour or small-sized WDSs with simple topology and limited complexity. This lack of complex case studies has often hindered the demonstration of the potential of hydraulic models and of the optimization approaches relying on their use. In this work, we present a case study about a real large WDS. The system is composed of approximately 3000 pipes (>170km) and 3000 demand nodes (corresponding to 50,000 users) that are spread across a hilly area over a 200 m elevation gradient. Water is provided by ten wells and it is distributed by five pumping stations and four tanks at different elevations. Pump operation is partly automatically controlled by water levels in tanks and partly by a fixed temporal schedule. This complexity results in a nontrivial hydraulic behaviour that is well reproduced by our hydraulic model. The model is also used with a multi-objective genetic algorithm solver to identify different operational scenarios that lead to a reduction of energy consumption and water leakages.

Effect of Decreasing Water Levels on the Spawning Rate and Egg Count of Female Crayfish Procambarus (Austrocambarus) llamasi (Villalobos, 1955)

Three different water levels were assessed to establish their role in Procambarus llamasi spawning synchronization. A total of 132 crayfish were used for this assay, 120 were female and 12 were male FI (reproductive male stage), with an average initial size of 45 mm total length and 2.5 g in weight. P. llamasi were produced under controlled conditions at CINVESTAV-Merida, Yucatan, Mexico. The experimental system consisted of 12 plastic tanks of 0.60×0.34×0.28 m, equipped with water recirculation, biological filters, individual PVC shelters, a constant water temperature of 26oC and total darkness. Decreasing water levels in the crayfish tanks showed an important negative effect of this factor on most of the biological parameters measured, including the spawning rate and the number of eggs spawned by females. Spawning female sizes in low water levels were smaller and with fewer eggs than in the other levels. These results revealed an important relationship between water level and spawning rate for P. llamasi.

Relieving Pressure: Optimizing Water Distribution Pressure Management at Valley of the Moon Water District

Efficiently managing pressure in a water distribution network is an issue for water utilities worldwide. Utilities must maintain a delicate balance between lowering the pressure as much as possible to reduce water loss and electricity usage, while keeping pressure high enough to maintain the required level of service. In this paper, we describe how we created and deployed an advanced decision support solution to help the Valley of the Moon Water District (VOMWD) in Sonoma County, California improve its pressure management. Our solution enables VOMWD to efficiently manage water pressure in its network and better handle the pressure changes resulting from seasonal variations in demand. It provides a comprehensive view of the pressure status in the network and incorporates a novel optimization algorithm and problem formulation, which efficiently solve a nonconvex optimization problem and provide recommendations for demand and input pressure changes in the network. Following the deployment of our solution, VOMWD reduced the number of leaks and bursts by 16 percent compared to the previous year and by 19 percent compared to the average of the previous three years. Less quantifiable results included a reduction in pressure spikes and improvements in tank water levels and water turnover. Our solution has widespread applicability; therefore, we plan to use it to help water utilities worldwide significantly improve their pressure-management capabilities.

Experimental Study on Simultaneous Desulfurization and Denitrification by Ozone Oxidation Combined with Alkaline Wastewater Washing

It is important to develop low cost and efficient technique for simultaneous removal of SO2and NOXfrom flue gas. In this paper, ozone oxidation and alkaline wastewater washing process was employed for flue gas desulfurization and denitrification in a 75t/h coal-fired boiler. In order to optimize the operation parameters for SO2and NOXremoval, the influence of several parameters, such as molar ratio of [O3]/[NO] and flue gas temperature on the oxidation rate of NO, oxidation rate of NO, alkaline water level in aeration tank, alkaline water rate and mole ratio of [NaOH/ (SO2+NOx)] on the removal efficiency of SO2and NOXhave been studied. The experimental results showed that molar ratio of [O3]/[NO] had limited effect on the oxidation of SO2, while NO oxidation efficiency improved with the increase of [O3/NO] molar ratio and it reached to ~ 90% at molar ratio of [O3]/[NO] = 1.4. Flue gas temperature performed slight influence on the oxidation of NO in the range of 60 to 120 °C, and had adverse impact on the removal of SO2and NOX. NOXremoval rate was enhanced with increasing NO oxidation rate and achieved to a high level at NO oxidization rate of ~50%. Mole ratio of [NaOH/ (SO2+NOx)] had significant impact on the removal rate of NOX, while it showed limited effects on that of SO2. The increase of alkaline aeration water level and alkaline water rate would definitely lead to a higher removal rate for both SO2and NOX. An optimized removal rate of 93.6% for SO2, 77.6% for NOXand 99.1% for dust were obtained under the water level of 20cm and volume of 74.5t/h.

A study on performance optimization of a toilet by measuring accumulated flow rate of a trapway

When water shortages occur, toilet water-saving becomes an effective way to solve the problem. We developed a new method that utilizes the accumulated flow rate to predict the flushing performance and to obtain design data for the development of high-efficiency toilets. The results showed that the length and shape of the trapway are the most important factors for flushing performance, and additional water saving can be achieved by delaying the opening of the trapway outlet valve. In addition, the tank water level in the water tank needs to be optimized considering siphon intensity as well as siphon duration. In conclusion, the toilet was optimized up to 6.5 kg of water using 60 mm diameter flexible tube by the method of accumulated flow rate measurement. In the future, the development of an ultra high efficiency toilet below 4.5 kg will be tried utilizing the method.

Application of GPC Algorithm in Level Control System

In order to improve the dependability and security of the lever control system, we introduced the generalized predictive control (GPC) algorithm. We used MATLAB/Simulink program development tools to control the double capacity water tank. At first, we used the water tank level control device as the object and set up a mathematical model of the control system. Then we put forward the generalized predictive control algorithm based on the model. The simulation results show that the presented algorithm has a good dynamic response performance, fast-track settings, and a preferable control effect. Experimental results show that the improved methods are reasonable and practicable.

Control Simulation for Three Tank Water Level

Three-tank liquid level system of its vessels belonging to non-linear relationship between the coupling. In this paper, three tank level control experimental system as the research object, the establishment of the level system model, and according to the experimental requirements: upper, middle tank to stabilize the value of the lower tank eventually reaches a given value, forming a typical third-order object of study.

Parameter Setting Based on JGPC Algorithm for Liquid Level Control System

Double-tank water level control system is a nonlinear system in ship. It has long cubage delay and bad anti-jamming ability in ordinary. In order to improve the dependability and security of the lever control system, a improved generalized predictive control (JGPC) algorithm was introduced. We set up a mathematical model of control system with the water tank level control device as the object. Based on the mode, the improved generalized predictive control algorithm was put forward and introduced the parameter setting of JGPC algorithm. The simulation results show that the presented algorithm has a good dynamic response performance, fast-track settings, and a preferable control effect. Experimental results show that the improved methods are reasonable and practicable.

The performance of rainwater tanks for stormwater retention and water supply at the household scale: an empirical study

Urban stormwater run-off degrades the ecological condition of streams. The use of rainwater tanks to supplement water supply can reduce the frequency and volume of urban stormwater run-off that is otherwise conveyed directly to streams via conventional stormwater drainage systems. Few studies, however, have examined the use of tanks in the context of managing flow regimes for stream protection, with most focussed uniquely on their water conservation benefits. We used measured tank water level data to assess the performance of 12 domestic rainwater tanks against the dual criteria of their ability to (i) reduce potable mains water usage and (ii) retain run-off from rainfall events and thus reduce the volume and frequency of stormwater run-off. We found that five households relied almost entirely on tank water. Three of the tanks achieved stormwater retention performance approaching that of the same area of pre-developed land, although nine did not – a consequence of limited demand and small tank capacity. Our results suggest that tank water usage can result in substantial reductions in mains water use, if regular and sufficiently large domestic demands are connected to tanks. In many cases, such demands will also result in the best stormwater retention performance. Our results highlight an opportunity to design tank systems to achieve multiple objectives. Application of similar analyses in different locations will help to optimize tanks for simultaneous water supply and stormwater retention purposes. Copyright © 2014 John Wiley & Sons, Ltd.

Background Leakage Assessment for BBLAWN

Abstract Proposed solution approach is based on trial and error methodology using heuristic methods with simulation. To achieve the optimal solution, customized researched tools were developed for WDS optimization. Custom research tools are based on the TOOLKIT for the EPANET2. For design decisions also commercially available tools are used, carrying out comparison of various network structures (parallel pipe alternatives). The final result includes the change in 5 pipe diameters/pipe roughness coefficient C value; the installation of 80 pressure reducing valves and the change of 2 pump elements. Pumping schedule based on water tank levels was also optimized.

Air-Water Tests on Counter-current Flow Limitation at Lower End of Vertical Pipes Simulating Lower Part of Steam Generator U-tube

Air-water tests on counter-current flow limitation (CCFL) were carried out using vertical pipes with the diameter of D=20 mm and a sharp lower edge which simulated the lower part of U-tubes in a steam generator. Flow patterns were observed to identify the location of CCFL occurrence, and effects of the pipe length L and the water level in the upper tank h on CCFL were measured under the conditions of L=100-700 mm and h=100-600 mm. As a result, CCFL appeared at the upper end under the conditions of L/D=5 and h/D=5, but at the lower end for L/D≧15 and h/D=5～30. In the case of the CCFL occurrence at the lower end, L and h did not affect CCFL characteristics. Using the Wallis parameters, JG* and JL*, a CCFL correlation for the sharp lower edge was derived. The CCFL constant, which is the value of JG*1/2 at JL*1/2=0, was C=0.73±0.02.

Performance Estimation of Vertical Inflow Diffuser for Temperature-stratified Type Thermal Storage Tank by CFD Analysis - Effect of Tank Water Level and Step Change of Flow Rate on Temprature Distribution -

Performance Estimation of Vertical Inflow Diffuser for Temperature-stratified Type Thermal Storage Tank by CFD Analysis - Effect of Tank Water Level and Step Change of Flow Rate on Temprature Distribution -

Real-time Optimal Control of Water Distribution Systems

This study attempts to develop a real-time optimal control model for water distribution network. The model aims to minimize operation cost by optimal control of pump system, while satisfying various operational constraints under demand fluctuations and energy tariff variations throughout operation period. The real-time control is realized using SCADA system, by which monitoring data is collected and the obtained control decisions are implemented. Optimal pump scheduling model is developed by combining demand forecasting, hydraulic simulation, and optimization models. Decision variables include pump on/off (binary code of 0/1) schedules for fixed-rate pumps for each time-step over pre-defined operation time horizon. Various operational constraints are applied such as, 1) maintaining system pressure near allowable minimum pressure avoiding excessive pressure to reduce energy consumption and non-revenue water, 2) maintaining tank water level within an appropriate range, and 3) peak energy consumption limit for each pump station. The proposed model follows four steps; step1) demand forecasting, step 2) system update based on SCADA monitoring data, step 3) optimizing pump/valve control decision, and 4) implementing current time control settings.

Influences of boil-off on the behavior of a two-phase natural circulation loop

This experimental study investigates the thermal hydraulic behavior and boiling mechanisms present in a natural circulation loop experiencing boil-off. Extended duration tests with inventory loss were conducted to examine the transient behavior of a test loop under constant heat load. Five different stages of natural circulation flow were identified: single-phase heating, transitional nucleate boiling, hydrostatic head fluctuations, stable two-phase flow, and geysering. The water level in the storage tank was observed to play an important role in the stability of the system as it directly influences the hydrostatic pressures and, therefore local saturation temperatures. It would found that changes in inventory can shift the boiling boundary to different segments of the loop, whose geometry and orientation dictate the flow regime and ultimately the system behavior. With continued loss of inventory, a break in the loop occurs and induces flow stagnation with geysering in the heated region. Further operation results in severe degradation of heat removal, with a potential for burn out and possible structural damage. For safety-related applications, the venting of steam can extend the long-term cooling time window for heat removal and is of significant practical interest.

Monitoring of Water and Salt Transport during the Leaching Process under Different Water Level in an Experimental Tank

Monitoring of coastal saline soil water and salt transport is of great value on the soil physics and irrigation studies. In this paper, a vertical infiltration experiment was conducted to monitor the vertical variation of resistivity in the leaching process under different water level in an experimental tank by the designed automatic monitoring device. The experimental results showed regardless of whether the groundwater exist, the resistivity peak moved down in the curve of leaching, and the desalination occurred from the top to bottom, the desalination depth remains the same with the same leaching amount. However, the groundwater reduced the speed of water and salt transport and affected the water and salt migration of upper soil due to the capillary force.

Liquid level measurement system using capacitive sensor and optical sensor

Measurement of liquid level in storage and processing vessels, tanks, wells, reservoirs and hoppers is commonly needed. The several different ways to measure the liquid level of oil or water tank have been provided such as an electrostatic capacity, a supersonic waves and an optical science etc. In the study, we have constructed the stable and efficient measurement system to measure the level of liquid at real-time and to get accurate measurement of the maximum and minimum level of the tank. For this purpose, we suggest double sensing methods by adopting both capacitive and optical sensing. The experimental results, presented in this paper, illustrate the effectiveness of the proposed method under different sensing methods.

On the Seismic Performance of Elevated Water Tanks and their Control Using TLDs

The post-earthquake function of elevated water tank structures so as respond to the civil water requirements is of extreme significance. These structures are, however, extremely vulnerable to seismic conditions and there has been substantial damage/failure of several such structures during major earthquakes. A review of the damage and performance of some elevated water tanks subjected to earthquakes is presented in this paper. An investigation is also made on the seismic vibration control of elevated water tank structures by using Tuned Liquid Dampers (TLDs). A frequency domain formulation for the transfer function of the elevated water tank with attached TLDs is developed. Numerical studies on a reinforced concrete elevated water tank with shaft type support are carried out. The effect of detuning on the performance of the TLDs due to the change in the structural frequencies resulting from the fluctuating water level in the water tank is also examined. Results indicate that it is possible to design a fairly robust and effective TLD system for the seismic vibration mitigation of the considered elevated water tank.

English

  This paper presents an electrical model for studying the process behaviour of a sachet water production plant. In this model, the mechanical components of the plant such as the connecting pipes, the water tanks and the water filter were represented by resistors, capacitors and an inductor, respectively. A state equation was developed as a mathematical model of the electrical circuit. In this equation, resistors, capacitors and inductor representing the restriction of the pipes, the capacity of the tanks and the filtration of the filter respectively, were used as variable parameters to generate the state variables of the state equation. This mathematical model was used to simulate the effects of varying the electrical parameters (and) on the state variables ( and) representing the restriction of the connecting pipes, the water levels () in the water tanks and the filtration of the water filter, respectively. Insight into the response curves will indeed form the basis for studying the process control of the sachet water processing plant.   Key words: Mathematical model, analogous system, state equation, control, modeling, simulation

ERPWS: An Energy Efficient Routing Protocol for Conductive Sensor based Water Level Monitoring and Control System using Zigbee and 74HC14 Inverter

In this paper we have shown how to use conductive sensor, Zigbee and 74HC14 Inverter to monitor the water level and to control the working of pump. This project is designed to automatically fill the over head tank when it gets empty and monitor the water level in it. The motor is switched ON when the water level in the overhead tank drops below a pre fixed low level (on point) and puts off the motor when water level rises up to pre fixed high level (off point).The motor is also switched off during the following conditions: when the sump water is exhausted before filling overhead tank, pump running dry, mains voltage fluctuations. We also introduce an energy efficient routing protocol for Wireless Sensor Networks (ERPWS) for Conductive Sensor based Water Level Monitoring and Control System using Zigbee (XBEE 802.15.4) in terms of energy consumptions, the packet loss ratio, network lifetime and the average delivery delay. The XBEE used here is XBEE Pro Series 1(XBP24-AWI-001) and IC used is 74HC14 Hex Inverting Schmitt trigger. Simulation results have been obtained by using NS2 simulator. The evaluation results show that the energy consumption of routing using ERPWS is significantly lower than LEACH and traditional routing protocols.