scholarly journals Simulation and Experimental Analysis on the Load Characteristics of a Temperature-Control Curtain in a Thermally-Stratified Reservoir

2020 ◽  
Vol 10 (4) ◽  
pp. 1461
Author(s):  
Jijian Lian ◽  
Chunxi Liu ◽  
Haijun Wang ◽  
Fang Liu ◽  
Wenhe Lu ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Water Temperature ◽  
Temperature Control ◽  
Model Simulation ◽  
Area Ratio ◽  
Temperature Stratification ◽  
Selective Withdrawal ◽  
Blocking Rate ◽  
Water Blocking ◽  
Load Characteristics

Low-temperature discharged water from thermally-stratified reservoirs in spring and summer will have a negative environmental impact on fish breeding and agricultural irrigation downstream. The temperature-control curtain (TCC) is a selective withdrawal structure that can effectively change the discharged water temperature. Compared with a traditional selective withdrawal project, a TCC project has the advantages of low cost and simple construction and can even be added to operating reservoirs without impacting power generation. Analysis of the load characteristics is the key to the application of TCC engineering. This paper establishes a three-dimensional numerical model simulation and verifies it with physical model experimental results. The crucial parameters affecting the load characteristics of TCC are investigated, including the water blocking rate, area ratio, inclination ratio, inflow velocity, and water temperature stratification ratio. The results show that: (1) This numerical simulation approach can be used to predict the drag coefficient and the load of a TCC; (2) the water blocking rate has the greatest influence on the drag coefficient, and it is the most critical indicator of the TCC load; and (3) the drag coefficient exponentially increases with an increasing water blocking rate, quadratically increases with an increasing area ratio, linearly increases with an increasing inclination ratio, and linearly increases with an increasing water temperature stratification ratio.

scholarly journals Influence of the Thermometer Inertia on the Quality of Temperature Control in a Hot Liquid Tank Heated with Electric Energy

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 4039
Author(s):  
Dawid Taler ◽  
Tomasz Sobota ◽  
Magdalena Jaremkiewicz ◽  
Jan Taler
Keyword(s):  
Water Temperature ◽  
Time Constant ◽  
Temperature Control ◽  
Complex Structure ◽  
Small Diameter ◽  
Hot Water ◽  
Temperature Control System ◽  
Water Tank ◽  
Water Storage Tank

This paper presents the medium temperature monitoring system based on digital proportional–integral–derivative (PID) control. For industrial thermometers with a complex structure used for measuring the temperature of the fluid under high pressure, the accuracy of the first-order model is inadequate. A second-order differential equation was applied to describe a dynamic response of a temperature sensor placed in a heavy thermowell (industrial thermometer). The quality of the water temperature control system in the tank was assessed when measuring the water temperature with a jacketed thermocouple and a thermometer in an industrial casing. A thermometer of a new design with a small time constant was also used to measure temperature. The quality of water temperature control in the hot water storage tank was evaluated using a classic industrial thermometer and a new design thermometer. In both cases, there was a K-type sheathed thermocouple inside the thermowell. Reductions in the time constant of the new thermometer are achieved by means of a steel casing with a small diameter hole inside which the thermocouple is precisely fitted. The time constants of the thermometers were determined experimentally with a jump in water temperature. A digital controller was designed to maintain the preset temperature in an electrically heated hot water tank. The function of the regulator was to adjust the power of the electrical heater to maintain a constant temperature of the liquid in the tank.

A Wireless Sensor Network Based Water Temperature Stratification Monitoring System for Aquaculture of Sea Cucumber

2011 ◽  
Vol 9 (3) ◽  
pp. 1094-1100 ◽  
Author(s):  
Ji Chen ◽  
Daoliang Li ◽  
Shangfeng Du ◽  
Yaoguang Wei ◽  
Haijiang Tai
Keyword(s):  
Wireless Sensor Network ◽  
Water Temperature ◽  
Sensor Network ◽  
Monitoring System ◽  
Sea Cucumber ◽  
Temperature Stratification ◽  
Wireless Sensor

SCM Based High Precision Temperature Controller Design

2013 ◽  
Vol 313-314 ◽  
pp. 549-552 ◽  
Author(s):  
Zhen Hua Han ◽  
Ze Hu Feng
Keyword(s):  
Water Temperature ◽  
Real Time ◽  
Temperature Control ◽  
Control Method ◽  
Controller Design ◽  
Heating Time ◽  
Single Chip ◽  
The Real ◽  
Pid Algorithm ◽  
Analog Voltage

t is designed by adopting SUNPLUS SPCE061A version 16-bits Single Chip Microcomputer; it has realized functions as manual setting temperature, automatic temperature control, showing the real-time temperature of water. The testing mode of water temperature adopts AD590 version integrated analog temperature sensor to perceive the temperature of water in vessels and uses operational amplifier to amplify minute analog voltage signal outputted by sensor. It employs keyboard scan mode to set target temperature (40°C~90°C) and displays dynamically the real-time temperature of water with digestion. The system controls the guide circuit and closing of the heating device by using relay circuit, achieving the aim of keeping design temperature constant essentially. PID algorithm is adopted in water temperature control method. The proportion, integration and differential constant in PID algorithm are debugged with experiments in order to control the proportion of heating time and reduce the adjusting time of the system. The system boasts the advantages of high controlling precision, stability and reliability, flexible operation, strong currency.

Experimental Study on the Hydrodynamic Characteristics of Artificial Reefs

2019 ◽  
Author(s):  
FenFang Zhao ◽  
Muk Chen Ong ◽  
Yanli Tang ◽  
Xinmeng Wang
Keyword(s):  
Experimental Study ◽  
Drag Coefficient ◽  
Coastal Ecosystems ◽  
Hydrodynamic Forces ◽  
Area Ratio ◽  
Artificial Reefs ◽  
Hydrodynamic Characteristics ◽  
Open Area ◽  
Model Experiments ◽  
Different Shapes

Abstract Artificial reefs (ARs) are structures constructed on the seabed to attract and concentrate fish and to potentially improve and rehabilitate coastal ecosystems. In order to investigate the hydrodynamic characteristics of ARs, a series of model experiments of cubic artificial reefs are carried out in the flume. The model reefs are made of acrylic material with different shapes of opening and various open-area ratios. The hydrodynamic forces of the models are measured in the experiments. The changes of drag coefficient with respect to the open-area ratio and the flow-facing angle of attack are investigated and discussed respectively.

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