MODELLING AND SIMULATION OF HEAT TRANSFER PROCESSES FOR HEAT EXCHANGERS USED IN WASTEWATER TREATMENT

2016 ◽  
Vol 15 (5) ◽  
pp. 1027-1033 ◽  
Author(s):  
Timea Gabor ◽  
Viorel Dan ◽  
Ancuta Elena Tiuc ◽  
Ioana Monica Sur ◽  
Iulian Nicolae Badila
Keyword(s):  
Heat Transfer ◽  
Wastewater Treatment ◽  
Heat Exchangers ◽  
Modelling And Simulation ◽  
Transfer Processes

Heat Transfer on Parallel Plate Heat Exchangers in an Oscillatory Flow

2010 ◽  
Author(s):  
Xiaoan Mao ◽  
Lei Shi ◽  
Artur J. Jaworski ◽  
Wasan Kamsanam
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Temperature Gradient ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Oscillatory Flow ◽  
Quantitative Description ◽  
Solid Boundary ◽  
Acoustic Excitation ◽  
Transfer Processes

In thermoacoustic devices, an acoustic wave interacts with internal solid structures such as thermoacoustic stacks (regenerators), to either produce acoustic power due to an imposed temperature gradient, or to produce a heat pumping effect by an acoustic excitation. A cold and hot heat exchangers are usually placed on either side of these internal solid structures to enable heat communication between the thermoacoustic devices and their surroundings. Heat exchangers of various geometries have been extensively studied in steady flows and results are available from a collection of published articles and handbooks. However, there is still a lack of data for heat exchangers in an oscillatory flow, because the interaction of oscillatory flow with the solid boundary is governed by complicated fluid flow and heat transfer processes that are not fully understood. This work is a step towards a better understanding of the heat transfer mechanisms in the acoustically induced oscillatory flow within thermoacoustic systems, in particular obtaining the quantitative description of the heat transfer between heat exchangers and the stack. The assembly of a stack and heat exchangers is replaced by a simplified “stack-less” pair of heat exchangers, in order to focus on the generic heat transfer processes rather than the intricacies of practical thermoacoustic systems. The fins of the hot and cold heat exchangers are kept at constant temperatures by virtue of resistive heating and water cooling, respectively. Planar Laser Induced Fluorescence (PLIF) and Particle Image Velocimetry (PIV) are used to obtain the temperature and velocity fields around the fins. The heat flux between the heat exchanger fins and the fluid is analyzed phase-by-phase. The time dependent local heat transfer coefficient is obtained from the temperature gradient in the thermal boundary layer. The measurements are conducted at various levels of acoustic excitation in order to study the correlation between the non-dimensional heat transfer coefficient Nu and the Reynolds number. The effect of the flow behaviour at the end of the plates on the temperature field in the region is also studied. It is hoped that this work could lead to a better understanding of heat transfer on short plates in the acoustically induced oscillatory flows.

scholarly journals Heat Transfer in the Ducts of the Cooling Systems of Traction Motors

2018 ◽  
Vol 7 (4.3) ◽  
pp. 315
Author(s):  
A А. Aleksahin ◽  
A V Panchu ◽  
L A. Parkhomenko ◽  
H V. Bilovol
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Cooling System ◽  
Transfer Processes ◽  
New Energy ◽  
Working Media ◽  
Artificial Heat ◽  
The Impact

Requirements for increasing thermal efficiency heat exchangers, which lead to energy saving, material and reduction cost, and as a result of reducing the impact on the environment, led to the development and use of various methods of increasing heat transfer. These methods are called intensification of heat transfer processes. Intensification of heat and mass transfer processes is of great importance for making progress in improving the existing and creation of new energy and heat-exchange equipment. Among the ways of intensifying heat transfer, the swirling of flows of working media is one of the simplest and most common methods and is widely used in energy-intensive channels of nuclear power plants, heat exchangers, aeronautical and rocket and space equipment, chemical industry and other technical devices. We have proposed formulas to determine the cooling air velocity necessary to ensure the required temperature condition of the traction motor assemblies. Decrease in the power of fans in the cooling system using the artificial heat transfer intensification in the ducts was estimated based on the generalization of the results of calculations.  

Study of the Heat-Transfer Processes of Tubular Elements of Ground Heat Exchangers

2015 ◽  
Vol 88 (3) ◽  
pp. 676-680
Author(s):  
K. Kusaiynov ◽  
N. N. Shuyushbayeva ◽  
K. M. Shaimerdenova ◽  
Zh. G. Nurgalieva ◽  
N. N. Omarov
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Transfer Processes ◽  
Ground Heat Exchangers

scholarly journals Comprehensive analysis of transfer processes in modern high-temperature heat exchangers

2019 ◽  
Vol 41 (3) ◽  
pp. 26-32
Author(s):  
B. Soroka ◽  
V. Zgurskyi
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchangers ◽  
Exchange Process ◽  
Comprehensive Analysis ◽  
Cfd Modeling ◽  
Tube Heat Exchanger ◽  
Transfer Processes ◽  
Temperature Heat ◽  
Heat Exchange Process

The CFD modeling of high-temperature tube heat exchanger has been carried out. The results of numerical analysis of internal and external secondary emitters’ (SEE) influence upon intensity and uniformity of resulting heat transfer have been presented and discussed. An internal SEE have the determining impact upon heat exchange process thus enhancing the resulting heat flux till extra 40%.

scholarly journals Optimization of heat transfer processes in the circuit of a nuclear power plant in order to increase it

2021 ◽  
Vol 3 (134) ◽  
pp. 79-86
Author(s):  
Svetlana Shvachich ◽  
Vladimir Bulychev ◽  
Kateryna Ternova
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Nuclear Energy ◽  
Secondary Circuit ◽  
Transfer Processes ◽  
Heat Carriers

The urgency of the work is due to the depletion of traditional fuel reserves and increasing the load on the biosphere because of emissions from burning coal, oil and gas. The solution of these problems are the development of nuclear energy. The advantages of nuclear energy are analyzed, namely: high calorific value of nuclear fuel, better economic indicators, less environmental pollution. The purpose of this work is to optimize the heat transfer processes in the secondary circuit of a nuclear power plant. It is proposed to take the second circuit of the third power unit of the Rivne nuclear power plant as the object of research. The need for knowledge of heat transfer processes and hydrodynamics is determined by the fact that nuclear reactors are energy-intensive thermal machines, in which these processes are manifested in a rather complex form. Therefore, measures to optimize heat transfer processes in the thermal circuit of the second circuit of the NPP in order to increase energy performance are considered. In order to remove from the system the hardness salts that settle on the walls of the equipment and impair the heat transfer processes, a reagent has been selected to bind the hardness salts. he addition of the PuroTech113 reagent to the working circuit of the secondary circuit made it possible to free the system from the deposition of hardness salts in it, as this reagent "binds" free calcium and magnesium ions. In turn, scale is no longer deposited on the walls of the heat exchange equipment, which allows to fully transferring the required amount of heat. Recalculation of the thermal balance showed that the efficiency of the unit is increased by 3%.The efficiency coefficient of the heat exchanger was chosen as the criterion of optimality. The efficiency of the heat exchanger in the general case is a function of the mode parameters, the scheme of mutual movement of heat carriers and features of hydrodynamics and heat transfer of real heat exchangers. The problem of optimizing the movement of heat carriers in intermediate heat exchangers is solved in paper.

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