Heat Exchanger Analysis Modified to Account for a Heat Source

2007 ◽  
Author(s):  
Vinod Narayanan ◽  
Murty Kanury ◽  
Jeromy Jenks
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Heat Source ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Source Term ◽  
Fluid Stream ◽  
Overall Heat Transfer Coefficient ◽  
Definition Of

The practice of determining the overall heat transfer coefficient using the classical definition of log-mean-temperature-difference in heat exchangers with a heat source term in the hot fluid stream is questioned. The motivation for this work arises from the heat exchanger analysis of an ammonia-water absorber heat exchanger where a heat-of-absorption source term arises in the solution side. A modified heat exchanger analysis is developed here with account for such a heat source. Results of the analysis are discussed and its utility in deducing the overall heat transfer coefficient from experimental measurements is demonstrated.

Heat Exchanger Analysis Modified to Account for a Heat Source

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
Vinod Narayanan ◽  
Murty Kanury ◽  
Jeromy Jenks
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Heat Source ◽  
Transfer Coefficient ◽  
Source Term ◽  
Experimental Measurements ◽  
Ammonia Water ◽  
Overall Heat Transfer Coefficient

A modified heat exchanger analysis is developed here that accounts for a heat source, which is assumed to be volumetrically uniform in the hot fluid. The motivation for this work arises from the analysis of an ammonia-water absorber heat exchanger where a heat-of-absorption source term arises in the solution side. Utility of the analysis in deducing the overall heat transfer coefficient from experimental measurements is demonstrated.

scholarly journals Effective Overall Heat Transfer Coefficient Solver in a Triple Concentric-Tube Heat Exchanger

2019 ◽  
Vol 70 (6) ◽  
pp. 2040-2043
Author(s):  
Sinziana Radulescu ◽  
Loredana Irena Negoita ◽  
Ion Onutu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Total Thermal Resistance ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient

A relation for calculation of the effective overall heat transfer coefficient in a triple concentric-tube heat exchanger is proposed. The relation of the effective overall heat transfer coefficient is obtained based on total thermal resistance and it is applied within a case study for thermal analysis of two triple concentric-tube heat exchangers with different geometries, hot fluids and operating conditions. Through case study it is found that the values of effective overall heat transfer coefficient can be obtained with acceptable errors, up to 3 % for both heat exchangers.

Heat Transfer Enhancement Analysis of Al2O3-Water Nanofluid Through Parallel and Counter Flow in Shell and Tube Heat Exchangers

2017 ◽  
Vol 16 (05n06) ◽  
pp. 1750020 ◽  
Author(s):  
S. Nallusamy ◽  
N. Manikanda Prabu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Counter Flow ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube

Heat exchanger plays an essential part in industrial sector in transferring the heat energy. Heat is exchanged between fluids in convection and conduction mode through the walls of the heat exchanger. If the heat transfer medium has low thermal conductivity, it will greatly limit the efficiency of the heat exchanger. Whenever the system acts subjected to an increase in the heat load, heat fluxes caused by more power and smaller size, cooling is one of the technical challenges faced by the industries. The objective of this research work is to evaluate the overall heat transfer coefficient through an experimental analysis on the convective heat transfer and flow characteristics of a nanofluid. In our experiment, the nanofluid consists of water and one percentage volume concentration of Al2O3-water nanofluid flowing through parallel and counter flow in shell and tube heat exchangers. About 50[Formula: see text]nm diameter of Al2O3 nanoparticles was used in this analysis and found that the overall heat transfer coefficient and convective heat transfer coefficient of nanofluid were slightly higher than those of the base liquid at same mass flow rate and inlet temperature. Here, there are three samples of dissimilar mass flow rates, which have been identified for conducting the experiments and their results are continuously monitored and reported. Finally, the observed results through an experimental investigation were presented and concluded that the enhancement of overall heat transfer coefficient is likely to be feasible by means of increasing the mass flow rate of base fluid and prepared nanofluid on the proportional basis.

scholarly journals Optimization of Shell and Tube Condenser for Low Temperature Thermal Desalination Plant

2021 ◽  
Vol 309 ◽  
pp. 01011
Author(s):  
R Elakkiyadasan ◽  
Kumar P Manoj ◽  
M Subramanian ◽  
N Balaji ◽  
M Karthick ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Pumping Power ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube

In the current work, attempt for enhancing the heat exchanger of the shell and tube by analyzing the various parameters. The heat exchanger is a device used to transfer heat between at least two fluids. In the different kinds of heat exchangers utilized in various industries, shell and tube heat exchangers are presumably the most adaptable and widely heat exchangers utilized in most industrial areas. Based on the relationship between different parameters such as tube velocity, overall heat transfer coefficient, mass flow rate, and pumping power, analysis is carried out. Results show that the tube velocity increases the overall heat transfer coefficient, total pressure drop and mass flow rate of water, Pumping Power, up to the certain limit and starts to decrease. So that the parameters can be optimized by conducting the experiments based on different input parameters. The parameters which influence the optimal result are researched and recommended.

scholarly journals Effect of nanoparticles on heat transfer in heat exchangers

2015 ◽  
Vol 37 ◽  
pp. 199
Author(s):  
Ali Mahrooghi ◽  
Mohammad Moghiman
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Water Pressure ◽  
Two Phase ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient

In this paper, forced convection flow and heat transfer of a Al2O3/Water nanofluid have beeninvestigated numerically by single and two phase (volume of fluid) models. Nanofluid flows inside the innertube of the isothermally concentric circular and sinusoidal double tube heat exchangers while hot pure waterflows in the outer tube. The single-phase and two-phase models is used to simulate the nanofluid forcedconvection of 2% and 3% volume concentrations. The renormalization group k-ε model is used to simulateturbulence in ANSYS FLUENT 15.0. Results show that the overall heat transfer coefficient increases withnanoparticle volume concentrations in the heat exchangers. The highest overall heat transfer coefficient rates aredetected, for each concentration and shape, corresponding to the highest flow rate for the sinusoidal tube heatexchanger . The maximum overall heat transfer coefficient enhancement is 220% for the particle volumeconcentration of 3% at the inner tube of concentric sinusoidal double tube heat exchanger corresponding to flowrate =10 LPM. The results reveal that the Al2O3/water pressure drop along the inner tube of circular andsinusoidal double tube heat exchanger increases by about 3% and 5% for volume concentrations of 2% and 3%,respectively, given flow rate compared to the base fluid.Comparison of these results with Rohit S. Khedkar‘spublished experimental data, showed good agreement.

scholarly journals Oil Refinery Heat Exchanger Network Cleaning Scheduling Strategy with Unit Cleanability Consideration

2020 ◽  
Vol 20 (1) ◽  
pp. 31
Author(s):  
Hairul Huda ◽  
Renanto Handogo ◽  
Totok Ruki Biyanto ◽  
Wei Wu ◽  
Vincentius Surya Kurnia Adi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Oil Refinery ◽  
Cleaning Procedure ◽  
Overall Heat Transfer Coefficient ◽  
Cleaning Procedures ◽  
Heat Requirement

Heat exchanger networks (HENs) play an important role in the chemical industries. Unfortunately, fouling is inevitable in heat exchangers operation. Therefore, the optimal cleaning procedure is required to restore heat exchangers' performance periodically. A systematic cleaning scheduling strategy for the heat exchanger network in an oil refinery is proposed in this work. There are 11 operating heat exchangers in an oil refinery to be reviewed. Different cleaning decision scenarios based on the overall heat transfer coefficient are explored for optimal cleaning schedule performance. The daily number of exchangers available to be cleaned i.e., the unit cleanability, is investigated while minimizing the energy consumption and the additional heat requirement due to the offline heat exchanger under cleaning procedure. The HEN performance and the energy-saving from the cleaning procedures are benchmarked with the uncleaned HEN. The results indicate that the cleaning procedure significantly increases the HEN performance and simultaneously reduces the heat requirement if compared to the untreated HEN benchmark. The possible conflicting situation is discussed when some heat exchangers are waiting to be cleaned due to the unit cleanability restriction, which allows the overall heat transfer coefficient to be below the allowed limit. Therefore, nonconflicting cleaning scheduling is also addressed in this work by relaxing the unit cleanability limit. Furthermore, the optimal cleaning schedule is also suggested for user reference. In this work, the optimum cleaning schedule with minimum energy consumption and maximum energy saving could be achieved when cleaning decision limit is set at 40% decrease of overall heat transfer coefficient. In the contrast, the lowest number of cleaning procedures is associated with 90% decrease in the overall heat transfer coefficient as the cleaning decision limit.

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.

Heat Transfer Performance of Different Nanofluids Flows in a Helically Coiled Heat Exchanger

2013 ◽  
Vol 832 ◽  
pp. 160-165 ◽  
Author(s):  
Mohammad Alam Khairul ◽  
Rahman Saidur ◽  
Altab Hossain ◽  
Mohammad Abdul Alim ◽  
Islam Mohammed Mahbubul
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Transfer Performance

Helically coiled heat exchangers are globally used in various industrial applications for their high heat transfer performance and compact size. Nanofluids can provide excellent thermal performance of this type of heat exchangers. In the present study, the effect of different nanofluids on the heat transfer performance in a helically coiled heat exchanger is examined. Four different types of nanofluids CuO/water, Al2O3/water, SiO2/water, and ZnO/water with volume fractions 1 vol.% to 4 vol.% was used throughout this analysis and volume flow rate was remained constant at 3 LPM. Results show that the heat transfer coefficient is high for higher particle volume concentration of CuO/water, Al2O3/water and ZnO/water nanofluids, while the values of the friction factor and pressure drop significantly increase with the increase of nanoparticle volume concentration. On the contrary, low heat transfer coefficient was found in higher concentration of SiO2/water nanofluids. The highest enhancement of heat transfer coefficient and lowest friction factor occurred for CuO/water nanofluids among the four nanofluids. However, highest friction factor and lowest heat transfer coefficient were found for SiO2/water nanofluids. The results reveal that, CuO/water nanofluids indicate significant heat transfer performance for helically coiled heat exchanger systems though this nanofluids exhibits higher pressure drop.

Performance Study of Heat Exchangers with Continuous Helical Baffles on Different Inclination Angles

2013 ◽  
Vol 655-657 ◽  
pp. 461-464 ◽  
Author(s):  
Su Fang Song
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Performance Study ◽  
Three Dimensional Model ◽  
Shell Side ◽  
Inclination Angles

The three-dimensional model of heat exchangers with continuous helical baffles was built. The fluid flow dynamics and heat transfer of shell side in the helical baffled heat exchanger were simulated and calculated. The velocity, pressure and temperature distributions were achieved. The simulation shows that with the same baffle pitch, shell-side heat transfer coefficient increased by 25% and the pressure drop decreases by 18% in helical baffled heat exchanger compared with segmental helical baffles. With the analyzing of the flow and heat transfer in heat exchanger in 5 different inclination angles from 11°to 21°, it can be found that both shell side heat transfer coefficient and pressure drop will reduce respectively by 86% and 52% with the increases 11°to 21°of the inclination angles. Numerical simulation provided reliable theoretical reference for further engineering research of heat exchanger with helical baffles.

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