scholarly journals A Parametric Study of the Impact of the Cooling Water Site Specific Conditions on the Efficiency of a Pressurized Water Reactor Nuclear Power Plant

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mohamed M. A. Ibrahim ◽  
Mohamed R. Badawy
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Nuclear Power ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Overall Heat Transfer Coefficient ◽  
Seawater Salinity ◽  
Fouling Factor ◽  
The Impact

In this study, the thermal analysis for the impact of the cooling seawater site specific conditions on the thermal efficiency of a conceptual pressurized water reactor nuclear power plant (PWR NPP) is presented. The PWR NPP thermal performance depends upon the heat transfer analysis of steam surface condenser accounting for the key parameters such as the cooling seawater salinity and temperature that affect the condenser overall heat transfer coefficient and fouling factor. The study has two aspects: the first one is the impact of the temperature and salinity within a range of (290 K–310 K and 0.00–60000 ppm) on the seawater thermophysical properties such as density, specific heat, viscosity, and thermal conductivity that reflect a reduction in the condenser overall heat transfer coefficient from 2.25 kW/m2 K to 1.265 kW/m2 K at temperature and salinity of 290 K and 0.00 ppm and also from 2.35 kW/m2 K to 1.365 kW/m2 K at temperature and salinity of 310 K and 60000 ppm, whereas the second aspect is the fouling factor variations due to the seawater salinity. The analysis showed that the two aspects have a significant impact on the computation of the condenser overall heat transfer coefficient, whereas the increase of seawater salinity leads to a reduction in the condenser overall heat transfer coefficient.

scholarly journals Design, Fabrication and Performance Evaluation of a Shell and Tube Heat Exchanger for Practical Application

2020 ◽  
Vol 5 (8) ◽  
pp. 835-845
Author(s):  
Bashiru Abdulmumuni ◽  
Adedeji Mathew Ayoade ◽  
Ologunye Opeyemi Buhari ◽  
Azeez Rasheed Olatunde ◽  
Fanifosi Johnson Olaniyi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Cold Water ◽  
Hot Water ◽  
Feed Water ◽  
Capacity Ratio ◽  
Overall Heat Transfer Coefficient ◽  
Fouling Factor

A heat exchanger is a device used to transfer thermal energy between two or more fluids, at different temperatures in thermal contact. This paper focuses on a shell-and-tubes heat exchanger that involves two fluids (hot water and cold water) in contact with each other while the cold water flows through the tubes and hot water through the shell. Heat exchangers have special and practical applications in the feed water cooler in the process industries, power plants, chemical plants, refineries, process applications as well as refrigeration and air conditioning industry. The design calculations were carried out to determine the specifications of essential parameters for the development of the heat exchanger, data generated from the theoretical formulae were used to fabricate the heat exchanger using some locally available and durable materials, and the performance of the system was evaluated. Some of the parameters evaluated include heat duty, capacity ratio, effectiveness, overall heat transfer coefficient, and fouling factor. The heat exchanger was tested under various flow conditions and the results obtained were as follows; cold water inlet temperatures of (26, 26, 26, 27and 27) ºC increased to (59, 44, 39, 47 and 35) ºC after (10, 7½, 6½  8,  and 6) minutes and the hot water temperatures decreased from (100, 80, 75, 87 and 73) ºC to (73, 59, 55, 62 and 50) ºC, respectively. The design data and test data were compared in terms of the heat duty, capacity ratio, effectiveness, overall heat transfer coefficient, and fouling factor, the deviation is found to be 22.87%, 13.99%, 8.98%, 43.30%, and 43.30% respectively. The results obtained proved that the heat exchanger was effective, reliable and provides a good technical approach to evaluate the thermal performance of the heat exchanger and useful in conducting heat and mass transfer practical in thermodynamics laboratory.

Numerical Simulation of Heat Transfer in Simultaneously Developing Flows in Parallel Rectangular Ducts

Volume 3 ◽  
2004 ◽  
Author(s):  
Hussien Al-Bakhit ◽  
Ahmad Fakheri
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Three Dimensional ◽  
Constant Heat ◽  
Fully Developed Flow ◽  
Overall Heat Transfer Coefficient ◽  
Flow Heat ◽  
The Impact

The F correction factor charts, or the ε-NTU relations all assume that the overall heat transfer coefficient is constant across the heat exchanger. The short lengths and the comparatively thick walls through which heat is conducted in microchannel heat exchangers preclude the existence of thermally fully developed flow over a large portion of the heat exchanger. In this study, a parallel flow heat exchanger is simulated numerically to determine the impact of different parameters on the performance and the accuracy of constant heat transfer coefficient assumption. It is shown that there is significant change in the overall heat transfer coefficient in the developing region and that the three-dimensional heat transfer in the heat exchanger wall must be included in the analysis.

Methods for enhancing thermal performances using ecofriendly R1225ye(Z) refrigerant through nano particles inserted in brine flow evaporator of VCRS

2020 ◽  
pp. 113-123
Author(s):  
R. S. Mishra
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Performance Enhancement ◽  
Nano Particles ◽  
Exergy Destruction ◽  
Overall Heat Transfer Coefficient ◽  
Lost Work ◽  
The Impact

Lot of literature is open on performance enhancement of vapour compression & vapour absorption refrigeration system (VCRS & VARS), in any case, investigators have experienced point by point energetic performances investigation in term of COP of VCRS. Researchers is examined the impact of nanofluids on thermal conductivity enhancement. Nevertheless, researchers had not described exergy principle using entropy generation principle for finding the irreversibility computation in components and system exergy destruction ratio (EDRrational) that can be defined as a rational EDR (i.e. which is a ratio of summation of system’s lost work in terms of exergy destruction of all components to exergy of fuel) as well as EDRsystem (i.e. it is a ratio of total lost work to exergy of product) of VCRS using HFO refrigerants (i.e.R1225ye(Z)) This paper primarily deals with comparison between three nano particles that are utilized in minor circuit of cooling heat exchanger, which improves cooling temperature as a result of enhance in COP. enhancement in first law efficiency (i.e. COP) by using CuO, Al2O3, & TiO2 was evaluated to be as 18.48%, 17.47%, & 15.95%, respectively alongside enhancement in cooling heat exchanger overall heat transfer coefficient by using CuO, Al2O3, & TiO2 was about 107.66%, 98.6%, & 86.4%, respectively. Similarly, enhancement in condenser overall heat transfer coefficient by using CuO, Al2O3, & TiO2 was about 11.24%, 10.77%, & 9.94%, respectively. Also, enhancement in exergetic performance by using CuO, Al2O3, & TiO2 was about 13.93 %, 12.94 %, & 11.49%, respectively.

scholarly journals A numerical model and validation of phase change material integrated thermoelectric radiant cooling panel

2019 ◽  
Vol 111 ◽  
pp. 01001
Author(s):  
Hansol Lim ◽  
Hye-Jin Cho ◽  
Seong-Yong Cheon ◽  
Soo-Jin Lee ◽  
Jae-Weon Jeong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Numerical Model ◽  
Surface Temperature ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Phase Change Material ◽  
Overall Heat Transfer Coefficient ◽  
Radiant Cooling ◽  
Change Material

A phase change material based radiant cooling panel with thermoelectric module (PCM-TERCP) is proposed in this study. It consists of two aluminium panels, and phase change materials (PCMs) sandwiched between the two panels. Thermoelectric modules (TEMs) are attached to one of the aluminium panels, and heat sinks are attached to the top side of TEMs. PCM-TERCP is a thermal energy storage concept equipment, in which TEMs freeze the PCM during the night whose melting temperature is 16○C. Therefore, the radiant cooling panel can maintain a surface temperature of 16◦C without the operation of TEM during the day. Furthermore, it is necessary to design the PCM-TERCP in a way that it can maintain the panel surface temperature during the targeted operating time. Therefore, the numerical model was developed using finite difference method to evaluate the thermal behaviour of PCM-TERCP. Experiments were also conducted to validate the performance of the developed model. Using the developed model, the possible operation time was investigated to determine the overall heat transfer coefficient required between radiant cooling panel and TEM. Consequently, the results showed that a overall heat transfer coefficient of 394 W/m2K is required to maintain the surface temperature between 16○C to 18○C for a 3 hours operation.

Enhancement of Heat Transfer Performance in Nuclear Fuel Rod Using Nanofluids and Surface Roughness Technique

2015 ◽  
Author(s):  
Kang Liu ◽  
Titan C. Paul ◽  
Leo A. Carrilho ◽  
Jamil A. Khan
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Nuclear Fuel ◽  
Three Dimensional ◽  
Pressurized Water ◽  
Bulk Fluid ◽  
Fuel Rod ◽  
Dimensional Surface

The experimental investigations were carried out of a pressurized water nuclear reactor (PWR) with enhanced surface using different concentration (0.5 and 2.0 vol%) of ZnO/DI-water based nanofluids as a coolant. The experimental setup consisted of a flow loop with a nuclear fuel rod section that was heated by electrical current. The fuel rod surfaces were termed as two-dimensional surface roughness (square transverse ribbed surface) and three-dimensional surface roughness (diamond shaped blocks). The variation in temperature of nuclear fuel rod was measured along the length of a specified section. Heat transfer coefficient was calculated by measuring heat flux and temperature differences between surface and bulk fluid. The experimental results of nanofluids were compared with the coolant as a DI-water data. The maximum heat transfer coefficient enhancement was achieved 33% at Re = 1.15 × 105 for fuel rod with three-dimensional surface roughness using 2.0 vol% nanofluids compared to DI-water.

The Effect of Baffles in Shell and Tube Heat Exchangers

2009 ◽  
Vol 62-64 ◽  
pp. 694-699 ◽  
Author(s):  
E. Akpabio ◽  
I.O. Oboh ◽  
E.O. Aluyor
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Proper Position ◽  
Process Industries ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube ◽  
Optimal Values ◽  
Side Flow

Shell and tube heat exchangers in their various construction modifications are probably the most widespread and commonly used basic heat exchanger configuration in the process industries. There are many modifications of the basic configuration which can be used to solve special problems. Baffles serve two functions: Most importantly, they support the tubes in the proper position during assembly and operation and prevent vibration of the tubes caused by flow-induced eddies, and secondly, they guide the shell-side flow back and forth across the tube field, increasing the velocity and the heat transfer coefficient. The objective of this paper is to find the baffle spacing at fixed baffle cut that will give us the optimal values for the overall heat transfer coefficient. To do this Microsoft Excel 2003 package was employed. The results obtained from previous studies showed that to obtain optimal values for the overall heat transfer coefficient for the shell and tube heat exchangers a baffle cut of 20 to 25 percent of the diameter is common and the maximum spacing depends on how much support the tubes need. This was used to validate the results obtained from this study.

Energy Efficient Hybrid Nanofluids for Tubular Cooling Applications

2014 ◽  
Vol 592-594 ◽  
pp. 922-926 ◽  
Author(s):  
Devasenan Madhesh ◽  
S. Kalaiselvam
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Volume Concentration ◽  
Thermal Characteristics ◽  
Hybrid Nanofluid ◽  
Tubular Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Flow Through ◽  
Hybrid Nanofluids

Analysis of heat transfer behaviour of hybrid nanofluid (HyNF) flow through the tubular heat exchanger was experimentally investigated. In this analysis the effects of thermal characteristics of forced convection, Nusselt number, Peclet number, and overall heat transfer coefficient were investigated.The nanofluid was prepared by dispersing the copper-titania hybrid nanocomposite (HyNC) in the water. The experiments were performed for various nanoparticle volume concentrations addition in the base fluid from the range of 0.1% to 1.0%. The experimental results show that the overall heat transfer coefficient was found to increases maximum by 30.4%, up to 0.7% volume concentration of HyNC.

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