Digital Correction of Readings Produced by Fluid Level Measurement Channels at NPPs Equipped with Sensors Having a Dead Zone

Vestnik MEI ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 119-125
Author(s):  
Ivan A. Voronkov ◽  
◽  
Aleksandr A. Kalashnikov ◽  
Keyword(s):  
Technological Process ◽  
Nuclear Power ◽  
Dead Zone ◽  
Working Fluid ◽  
Water Mixture ◽  
Digital Correction ◽  
Physical Measurements ◽  
Essential Change ◽  
Digital Methods ◽  
Hydrostatic Level

The introduction and development of computerized digital systems in modern power engineering has led in Russia to a full modernization of domestically produced nuclear power plant measurement systems. In particular, digital methods for correcting the readings of hydrostatic level sensors have been widely put in use since 2013. The experience gained from putting them in use was generalized in the reference and organizational and methodological literature in 2017. However, the subsequent results of preoperational adjustments carried out at newly designed nuclear power units and at those under construction have shown that some issues still remain unresolved in this application field. In particular, there is a need is to develop digital methods for correcting the readings produced by channels measuring the level of liquid media in pressurized process tanks if there occurs a sensor dead zone. The complexity of this problem is stemming from the fact that it is not possible to take the sensor dead zone into account by introducing a constant correction to the measurement channel readings in view of the technological process peculiarities. Thus, during the operation of nuclear power units, the water density in pressurized process tanks and vessels decreases from 980 to 590 kg/m3, and the vapor density increases from 0 to 100 kg/m3. Such changes give rise to complex thermal and physical interphase processes that occur under the conditions of large mass transfers of the vapor--water mixture. As a result, the sensor's dead zone boundary undergoes an essential change in the tank longitudinal section depending on the current values of the working fluid thermal and physical characteristics. To solve this problem, digital methods for online correction of measured level readings are proposed that take into account changes in the two-phase working medium (vapor--water) in the course of a continuous technological process. Nowadays, the introduction of digital methods for correcting the hydrostatic level sensor readings is especially relevant in connection with the development of industry programs aimed at increasing the capacity of newly designed and operating nuclear power units, which pose more demanding requirements to the accuracy of thermal and physical measurements and operational safety as a whole.

Multi-Fluid Gas Turbine Components Scaling for a Generation IV Nuclear Power Plant Performance Simulation

2018 ◽  
Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Theoklis Nikolaidis ◽  
Pericles Pilidis ◽  
Suresh Sampath
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Gas Turbine ◽  
Nuclear Power ◽  
Working Fluid ◽  
Simulation Tool ◽  
Closed Cycle ◽  
Performance Simulation ◽  
Working Fluids ◽  
Component Map

One major challenge to the accurate development of performance simulation tool for component-based nuclear power plant engine models is the difficulty in accessing component performance maps; hence, researchers or engineers often rely on estimation approach using various scaling techniques. This paper describes a multi-fluid scaling approach used to determine the component characteristics of a closed-cycle gas turbine plant from an existing component map with their design data, which can be applied for different working fluids as may be required in closed-cycle gas turbine operations to adapt data from one component map into a new component map. Each component operation is defined by an appropriate change of state equations which describes its thermodynamic behavior, thus, a consideration of the working fluid properties is of high relevance to the scaling approach. The multi-fluid scaling technique described in this paper was used to develop a computer simulation tool called GT-ACYSS, which can be valuable for analyzing the performance of closed-cycle gas turbine operations with different working fluids. This approach makes it easy to theoretically scale existing map using similar or different working fluids without carrying out a full experimental test or repeating the whole design and development process. The results of selected case studies show a reasonable agreement with available data.

Novel Combined Power and Cooling Thermodynamic Cycle for Low Temperature Heat Sources, Part II: Experimental Investigation

2003 ◽  
Vol 125 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Gunnar Tamm ◽  
D. Yogi Goswami
Keyword(s):  
Low Temperature ◽  
System Analysis ◽  
Waste Heat ◽  
Thermal Power ◽  
Experimental System ◽  
Thermodynamic Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Water Mixture ◽  
Theoretical Simulation

A combined thermal power and cooling cycle proposed by Goswami is under intensive investigation, both theoretically and experimentally. The proposed cycle combines the Rankine and absorption refrigeration cycles, producing refrigeration while power is the primary goal. A binary ammonia-water mixture is used as the working fluid. This cycle can be used as a bottoming cycle using waste heat from a conventional power cycle or as an independent cycle using low temperature sources such as geothermal and solar energy. An experimental system was constructed to demonstrate the feasibility of the cycle and to compare the experimental results with the theoretical simulation. Results showed that the vapor generation and absorption condensation processes work experimentally, exhibiting expected trends, but with deviations from ideal and equilibrium modeling. The potential for combined turbine work and refrigeration output was evidenced in operating the system. Analysis of losses showed where improvements could be made, in preparation for further testing over a broader range of operating conditions.

scholarly journals Thermodynamic analysis and simulation of a new combined power and refrigeration cycle using artificial neural network

2011 ◽  
Vol 15 (1) ◽  
pp. 29-41 ◽  
Author(s):  
Abdolreza Fazeli ◽  
Hossein Rezvantalab ◽  
Farshad Kowsary
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Heat Source ◽  
Exergy Efficiency ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Water Mixture ◽  
Artificial Neural

In this study, a new combined power and refrigeration cycle is proposed, which combines the Rankine and absorption refrigeration cycles. Using a binary ammonia-water mixture as the working fluid, this combined cycle produces both power and refrigeration output simultaneously by employing only one external heat source. In order to achieve the highest possible exergy efficiency, a secondary turbine is inserted to expand the hot weak solution leaving the boiler. Moreover, an artificial neural network (ANN) is used to simulate the thermodynamic properties and the relationship between the input thermodynamic variables on the cycle performance. It is shown that turbine inlet pressure, as well as heat source and refrigeration temperatures have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. In addition, the results of ANN are in excellent agreement with the mathematical simulation and cover a wider range for evaluation of cycle performance.

Application of Supercritical Fluids in Thermal- and Nuclear-Power Engineering

2021 ◽  
pp. 601-658
Author(s):  
Igor L. Pioro
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Supercritical Fluids ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Thermal Power Plants ◽  
Power Cycles

Supercritical Fluids (SCFs) have unique thermophyscial properties and heat-transfer characteristics, which make them very attractive for use in power industry. In this chapter, specifics of thermophysical properties and heat transfer of SCFs such as water, carbon dioxide, and helium are considered and discussed. Also, particularities of heat transfer at Supercritical Pressures (SCPs) are presented, and the most accurate heat-transfer correlations are listed. Supercritical Water (SCW) is widely used as the working fluid in the SCP Rankine “steam”-turbine cycle in fossil-fuel thermal power plants. This increase in thermal efficiency is possible by application of high-temperature reactors and power cycles. Currently, six concepts of Generation-IV reactors are being developed, with coolant outlet temperatures of 500°C~1000°C. SCFs will be used as coolants (helium in GFRs and VHTRs, and SCW in SCWRs) and/or working fluids in power cycles (helium, mixture of nitrogen (80%) and helium (20%), nitrogen and carbon dioxide in Brayton gas-turbine cycles, and SCW/“steam” in Rankine cycle).

A Totally Heat-Driven Refrigeration System Using Low-Temperature Heat Sources for Low-Temperature Applications

2019 ◽  
Vol 27 (02) ◽  
pp. 1950012 ◽  
Author(s):  
Zeynab Seyfouri ◽  
Mehran Ameri ◽  
Mozaffar Ali Mehrabian
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Rankine Cycle ◽  
Exergy Efficiency ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Water Mixture ◽  
Refrigeration System ◽  
Power Requirement ◽  
Temperature Heat

In the present study, a totally heat-driven refrigeration system is proposed and thermodynamically analyzed. This system uses a low-temperature heat source such as geothermal energy or solar energy to produce cooling at freezing temperatures. The proposed system comprises a Rankine cycle (RC) and a hybrid GAX (HGAX) refrigeration cycle, in which the RC provides the power requirement of the HGAX cycle. An ammonia–water mixture is used in both RC and HGAX cycles as the working fluid. A comparative study is conducted in which the proposed system is compared with two other systems using GAX cycle and/or a single stage cycle, as the refrigeration cycle. The study shows that the proposed system is preferred to produce cooling at temperatures from 2∘C to [Formula: see text]C. A detailed parametric analysis of the proposed system is carried out. The results of the analysis show that the system can produce cooling at [Formula: see text]C using a low-temperature heat source at 133.5∘C with the exergy efficiency of about 20% without any input power. By increasing the heat source temperature to 160∘C, an exergy efficiency of 25% can be achieved.

A Novel Combined Power and Cooling Thermodynamic Cycle for Low Temperature Heat Sources: Part II — Experimental Investigation

Solar Energy ◽  
2002 ◽  
Author(s):  
Gunmar Tamm ◽  
D. Yogi Goswami
Keyword(s):  
Low Temperature ◽  
System Analysis ◽  
Waste Heat ◽  
Thermal Power ◽  
Experimental System ◽  
Thermodynamic Cycle ◽  
Working Fluid ◽  
Water Mixture ◽  
Theoretical Simulation ◽  
Intensive Investigation

A combined thermal power and cooling cycle proposed by Goswami is under intensive investigation, both theoretically and experimentally. The proposed cycle combines the Rankine and absorption refrigeration cycles, producing refrigeration while power is the primary goal. A binary ammonia-water mixture is used as the working fluid. This cycle can be used as a bottoming cycle using waste heat from a conventional power cycle or an independent cycle using low temperature sources such as geothermal and solar energy. An experimental system was constructed to demonstrate the feasibility of the cycle and to compare the experimental results with the theoretical simulation. Results showed that the vapor generation and absorption condensation processes work experimentally, exhibiting expected trends, but with deviations from ideal and equilibrium modeling. The potential for combined turbine work and refrigeration output was evidenced in operating the system. Analysis of losses showed where improvements could be made, in preparation for further testing over a broader range of operating parameters.

The Liquid Metal Fuel Reactor Closed-Cycle Gas Turbine Power Plant

1956 ◽  
Author(s):  
L. D. Stoughton ◽  
T. V. Sheehan
Keyword(s):  
Power Plant ◽  
Liquid Metal ◽  
Gas Turbine ◽  
Nuclear Power ◽  
Reactor Fuel ◽  
Working Fluid ◽  
Closed Cycle ◽  
Fuel Reactor ◽  
Metal Fuel ◽  
Gas Turbine Power Plant

A nuclear power plant is proposed which combines the advantages of a liquid metal fueled reactor with those inherent in a closed cycle gas turbine. The reactor fuel is a solution of uranium in molten bismuth which allows for unlimited burn-up with continuous fuel make-up and processing. The fuel can either be contained in a graphite core structure or circulated through an external heat exchanger. The cycle working fluid is an inert gas which is heated by the reactor fuel before entering the turbine. A 15 MW closed cycle gas turbine system is shown to illustrate the application of this reactor.

Gravity-Assisted Heat Pipe With Strong Marangoni Fluid for Waste Heat Management of Single and Dual-Junction Solar Cells

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Kenneth M. Armijo ◽  
Van P. Carey
Keyword(s):  
Heat Flux ◽  
Solar Cells ◽  
Heat Pipe ◽  
Waste Heat ◽  
Working Fluid ◽  
Water Mixture ◽  
Heat Management ◽  
Strong Concentration ◽  
Electrical Efficiency ◽  
Pipe System

This study investigates the cooling of single and multijunction solar cells with an inclined, gravity-assisted heat pipe, containing a 0.05 M 2-propanol/water mixture that exhibits strong concentration Marangoni effects. Heat pipe solar collector system thermal behavior was investigated theoretically and semi-empirically through experimentation of varying input heat loads from attached strip-heaters to simulate waste heat generation of single-junction monocrystalline silicon (Si), and dual-junction GaInP/GaAs photovoltaic (PV) solar cells. Several liquid charge ratios were investigated to determine an optimal working fluid volume that reduces the evaporator superheat while enhancing the vaporization transport heat flux. Results showed that a 45% liquid charge, with a critical heat flux of 114.8 W/cm2, was capable of achieving the lowest superheat levels, with a system inclination of 37 deg. Solar cell semiconductor theory was used to evaluate the effects of increasing temperature and solar concentration on cell performance. Results showed that a combined PV/heat pipe system had a 1.7% higher electrical efficiency, with a concentration ratio 132 suns higher than the stand-alone system. The dual-junction system also exhibited enhanced performance at elevated system temperatures with a 2.1% greater electrical efficiency, at an operational concentration level 560 suns higher than a stand-alone system.

Theoretical investigation of a combined Kalina and vapour-absorption cycle

2015 ◽  
Vol 26 (1) ◽  
pp. 113-124
Author(s):  
Mohammad Tariq ◽  
Vinod Kumar Nema
Keyword(s):  
Boiling Point ◽  
Saturation Temperature ◽  
Dew Point ◽  
Working Fluid ◽  
Absolute Pressure ◽  
Water Mixture ◽  
Cooling Cycle ◽  
Point Temperature ◽  
Mixture Concentration ◽  
Vapour Mixture

A program has been developed to calculate enthalpies at the salient points (later referred to as stations) of a combined power and cooling cycle provided pressure, temperature, mixture concentration and condition are known at these points. The ammonia-water mixture, which is taken as the working fluid, may be at one of the following seven conditions namely, superheated vapour mixture, mixture of superheated component of ammonia and pseudo vapour component of water, saturated vapour mixture, wet vapour mixture, saturated liquid mixture, mixture of subcooled water and pseudo liquid ammonia and subcooled mixture of subcooled components of ammonia and water. The mixture boiling-point temperature and dew-point temperature, needed to establish the condition of the working fluid, are functions of absolute pressure, critical pressure and critical temperature of the mixture; later two depend on the mixture concentration and the corresponding critical values of water at the given station. Using typical values of the variables as listed above, enthalpies at all stations are predicted. The predicted enthalpies are close (within 3%) to those available in the literature except at two stations where the mixture was weak in ammonia and its temperature was either in the near vicinity of the mixture boiling-point temperature or below the saturation temperature of pure ammonia at the concerned pressure. Using the predicted values of enthalpies, thermal efficiency of the combined power and cooling cycle has been calculated.

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