Experimental study on the heat transfer characteristics of a nuclear reactor containment wall cooled by gravitationally falling water (original) (raw)
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IRJET- TEMPERATURE PROFILE AND THERMAL PERFORMANCE OF BOILING WATER REACTOR BASED POWER PLANT
IRJET, 2021
A recent BWR fuel assembly includes of 37 fuel rods and there are up to roughly 800 assemblies in a reactor. Reactor core size, desired reactor power output, and reactor power density are the consideration are based on the number of fuel assemblies in a specific. In our analysis capacity of nuclear power plant is approximately 1465 MW. Nuclear reactor core is generally made up of fuel elements in cylindrical shape and contains fuel pellets, helium gas gap and cladding material. In this paper our ultimate goal was to analyze the temperature drop across the fuel element, from the center of the fuel where the maximum temperature occurs, to the gas gap and then finally to the cladding surface. The physical and thermal properties of the fuel element are known. The Nuclear fuel element used in this analysis was uranium dioxide, which is the standard fuel element for Light Water Reactors. The thickness of the helium gas gap is kept small because of its very low thermal conductivity, hence it is not very good in conducting heat between two surfaces.
2018
Author(s): Greenop, Andrew | Advisor(s): Peterson, Per F; Makiharju, Simo A | Abstract: With the growing demand for clean, carbon free electricity around the globe due to industrialization and increasing populations, nuclear reactors will become a necessity to supplement power from intermittent renewable sources. Advanced reactor designs such as the Fluoride Salt-cooled High Temperature Reactor, or FHR, are especially desirable due to their small, modular design, their passive safety systems, and their smaller capital costs. The reactor’s small size, high temperatures, and single-phase molten salt coolant meant that conventional heat exchanger designs could not be used as the primary form of heat removal. This lead to the development of the Coiled Tube Gas Heater, or CTGH, so that the reactor could be coupled with an air Brayton reheat cycle. The CTGH is a shell-and-tube heat exchanger that uses an annular tube geometry to reduce the overall volume of the heat exchanger. In the FHR ...
This paper briefly reviews some of the work on advanced the liner cooling techniques - specifically laminated porous wall cooling, angled-multirole (effusion) cooling and composite metal matrix liner cooling. The concept definition, heat transfer design procedure and design problems including key materials and fabrication considerations associated with each basic concept will be reviewed. Combustion characteristics and pollutant emissions are studied for different fuels. The influence of droplet diameter on pollutant emissions at all conditions is studied. The fuel and oxidizer are supplied at ambient conditions. The concept of high swirl flows has been adopted to achieve high internal recirculation rates, residence time and increased dilution of the fresh reactants in the primary combustion zone, resulting in flameless combustion mode. Numerical computation has been applied to investigate the temperature field in a gas turbine combustion chamber. The simulation assumed that pressure imbalance conditions of air flow between primary and secondary inlets occur.
Thermal flow analysis of vertical combustion chamber waterwall tubes operation
MATEC Web of Conferences, 2018
In this paper will be presented an algorithm that allows to determine the temperature distribution in a vertical pipe through which is flowing the medium with high temperature and pressure. The method of pipe division into control volumes presented in paper allows to determine the temperature distribution on the pipe cross-section and to determine changes in its value at the pipe height. The issue will be solved by taking into account the variability of the parameters of the material from which the pipe is made and the parameters of the fluid, depending on the temperature. The applied algorithm allows to determine the change in the value of individual parameters in time, due to which it is a useful tool for analysis of the operation of the system in the initial stage of its work, as well as with variable parameters of flow. Nomenclature Across sectional area, m 2 c-specific heat, J/kgK d-diameter, m g-standard gravity, m/s 2 h-enthalpy, kJ/kg k-thermal conductivity, W/mK m-mass flow of the medium, kg/s p-pressure, Pa r-radius, m t-temperature of the medium, °C υ-velocity of the medium, m/s z-height, m Greek letters α-heat transfer coefficient, W/m 2 K β-the angle of inclination of the waterwall tube, ° Δφ-characteristic angle for the finite volume under consideration, rad Δz-height of finite volume, m θ-wall temperature, °C ρ-density, kg/m 3 τ-time, s Subscripts in-inner m-medium o-outer
Journal of Physics: Conference Series
When station blackout occurs on high temperature gas-cooled reactor, the decay heat will be absorbed by a residual heat dissipation system (known as cooling tank) which connected to the reactor cavity cooling system. The U-shaped heat pipe as passive cooling system is proposed as new feature of technology to absorb the decay heat in the high temperature gas-cooled reactor cooling tank, and to keep the water remains in its operating temperature and level. This research objective is to know thermal resistance of U-shaped heat pipe scale model based on variation of heat load and coolant velocity. The influence of water temperature in the circulating thermostatic bath as heat load on evaporator section and air velocity which flowed into the horizontal condenser fin were investigated experimentally. The heat loads were varied at water temperature of 45, 50, and 60°C. The air velocities were varied at 0.45, 0.83, and 1.06 m/s. The experiment result showed the lowest thermal resistance of 0.000027±0.0000000593 °C/W when U-shaped heat pipe was operated at hot water temperature of 60°C and air velocity of 1.06 m/s. The investigation result can be used as a model and initial knowledge to design large scale of U-shaped heat pipe as a passive cooling system in cooling tanks connected to high temperature gas-cooled reactor cavity cooling system. This result is also useful regarding to the thermal management of passive cooling process in cooling tank and it can improve the nuclear safety and be able to overcome the thermal problems caused by station blackout in high temperature gas-cooled reactor.
Pollutant emissions reduction and performance optimization of an industrial radiant tube burner
Experimental Thermal and Fluid Science, 2006
This paper presents the results of an experimental investigation performed upon a single-ended self-recuperative radiant tube burner fuelled by natural gas in the non-premixed mode, which is used in the steel industry for surface treatment. The main goal of the research activity was a systematic investigation of the burner aimed to find the best operating conditions in terms of optimum equivalence ratio, thermal power and lower pollutant emissions. The analysis, which focused on the main parameters influencing the thermal efficiency and pollutant emissions at the exhaust (NO x and CO), has been carried out for different operating conditions of the burner: input thermal powers from 12.8 up to 18 kW and equivalence ratio from 0.5 (very lean flame) to 0.95 (quasi-stoichiometric condition). To significantly reduce pollutant emissions ensuring at the same time the thermal requirements of the heating process, it has been developed a new burner configuration, in which a fraction of the exhaust gases recirculates in the main combustion region through a variable gap between the burner efflux and the inner flame tube. This internal recirculation mechanism (exhaust gases recirculation, EGR) has been favoured through the addition of a pre-combustion chamber terminated by a converging nozzle acting as a mixing/ejector to promote exhaust gas entrainment into the flame tube. The most important result of this solution was a decrease of NO x emissions at the exhaust of the order of 50% with respect to the original burner geometry, for a wide range of thermal power and equivalence ratio.
IRJET-A Review on Investigation of Shell and Tube Heat Exchanger For Different Parameter
A heat exchanger is a device that is used to transfer thermal energy (enthalpy) between two or more fluids, at different temperatures and in thermal contact The tube diameter, tube length, shell types etc. are all standardized and are available only in certain sizes and geometry. And so the design of a shell-and-tube heat exchanger usually involves a trial and error procedure where for a certain combination of the design variables the heat transfer area is calculated and then another combination is tried to check if there is any possibility of reducing the heat transfer area. A primary objective is the estimation of the minimum heat transfer area required for a given heat duty. Some experts studied on the design, performance analysis and simulation studies on heat exchangers. Modeling is a representation of physical or chemical process by a set of mathematical relationships that adequately describe the significant process behavior. These models are often used for Process design, Safety system analysis and Process control. A steady state model for the outlet temperature of both the cold and hot fluid of a shell and tube heat exchanger will be developed and simulated, which will be verified with the experiments conducted. And various models developed according to the change in physical parameters & results are obtained. These models were developed using latest computers tools like ANSYS, Fluent, and MATLAB etc.. The obtained results were also evaluated by comparing the same with the industrial operating exchanger and found satisfactory
Thermal Science, 2019
The article presents the method of determining the temperature distribution in waterwall tubes of the combustion chamber. To simulate the operating conditions of waterwall tubes have been selected the model with distributed parameters, which is based on the solution of equations of the energy, mass and momentum conservation laws. The purpose of the calculations is determining the enthalpy, mass-flow and pressure of the working fluid flowing inside the tubes. The balance equations have been transformed into a form in which spatial derivatives are on the left, and the right side contains time derivatives. Then the time derivatives were replaced with backward difference quotients, and the obtained system of differential equations was solved by the Runge-Kutta method. The analysis takes into account the variability of fluid parameters depending on the mass-flow at the inlet of the tube and heat flux on the surface of the tube. The analysis of fluid parameters was carried out based on op...
2019
Article history: Received 30 September 2018 Received in revised form 29 October 2018 Accepted 6 December 2018 Available online 18 March 2019 The multipurpose Irradiator in Indonesia with capacity of 2 MCi Co-60 radioactive source was built to support food security. When not operated, the Co-60 is stored in the pool to keep the radiation not to exposure to environment. The decay heat generation of Co-60 could increase the pool water temperature. To improve safety especially during SBO conditions, the pool water should be passively cooled using a vertical straight wickless-heat pipe. The objective of this experimental study is to investigate the heat transfer phenomena and the thermal performance of the vertical straight wickless-heat pipe as passive cooling system in the irradiator pool. Vertical straight wickless-heat pipe with inner diameter of 57 mm and total length of 1000 mm was charged with demineralized water of working fluid with filling ratio of 55%. This experiment was cond...