Determination of Optimum Concentration of Nanofluid for Process Intensification of Heat Transfer Using Corrugated Plate Type Heat Exchanger

2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Vijaya Kumar Talari ◽  
Sunil Kumar Thamida ◽  
R. C. Sastry

Abstract In this study cooling of hot water is taken up using a compact heat exchanger such as corrugated plate type heat exchanger and with utility fluid as a nanofluid prepared from mixing Al2O3 in water. In general a monotonic increase of 30 % to 70 % in overall heat transfer coefficient is observed for increase in nanofluid concentration as well as its flow rate. An optimum concentration of nanofluid is hence not possible to be found as heat transfer coefficient exhibited a monotonic trend. But there is a penalty for using nanofluid of higher concentrations in heat exchangers in the form of additional hydraulic power required to supply the nanofluid due its higher viscosity. Hence, as a novel approach, a target temperature drop of 15 °C for hot fluid (with constant flow rate) is assumed and the minimum critical flow rate of cold nanofluid of various concentrations required for achieving this is determined using simulation. For such a critical flow rate at various nanofluid concentrations, the determined hydraulic power (product of pressure drop and flow rate) exhibited a global minimum around 0.75 % volume concentration of Al2O3 in water. Thus this article presents the process intensification procedure for the heat exchangers using nanofluids as heat transfer enhancement option.

2021 ◽  
Vol 9 (1) ◽  
pp. 60-71
Author(s):  
Abeth Novria Sonjaya ◽  
Marhaenanto Marhaenanto ◽  
Mokhamad Eka Faiq ◽  
La Ode M Firman

The processed wood industry urgently needs a dryer to improve the quality of its production. One of the important components in a dryer is a heat exchanger. To support a durable heat transfer process, a superior material is needed. The aim of the study was to analyze the effectiveness of the application of cross-flow flat plate heat exchangers to be used in wood dryers and compare the materials used and simulate heat transfer on cross-flow flat plate heat exchangers using Computational Fluid Dynamic simulations. The results showed that there was a variation in the temperature out of dry air and gas on the flat plate heat exchanger and copper material had a better heat delivery by reaching the temperature out of dry air and gas on the flat plate type heat exchanger of successive cross flow and.   overall heat transfer coefficient value and the effectiveness value of the heat exchanger of the heat transfer characteristics that occur with the cross-flow flat plate type heat exchanger in copper material of 251.74725 W/K and 0.25.


2020 ◽  
Vol 216 ◽  
pp. 01124
Author(s):  
Shavkat Agzamov ◽  
Sevinar Nematova

The article discusses the features of the creation and use of efficient heat exchanger. Designs of pipes with a developed heat exchange is presented. The procedure for determining the degree of development of the heat exchanging surface, the heat transfer coefficient, and the calculation of the heat transfer equation are given. As a result of creating efficient heat exchangers, three main parameters are used: the pipe outside diameter; the estimated flow rate; the Prandtl number.


2020 ◽  
Vol 6 (11) ◽  
pp. 14-20
Author(s):  
Rohit Kumar Gaur ◽  
Dr. Shashi Kumar Jain ◽  
Dr. Sukul Lomash

A heat exchanger is a device used to transfer thermal energy between two or more liquids, between a solid surface and a liquid, or between solid particles and a liquid at different temperatures and in thermal contact where shell and tube heat exchangers contain a large number of tubes packed in a jacket whose axes are parallel to those of the shell. Heat transfer occurs when one fluid flows into the pipes while the other flows out of the pipes through the jacket. In industry, three-tube heat exchanger tubes are used as condensers, evaporators, sub cooler, heat recovery heat exchangers, etc. The three concentric tube heat exchanger is a constructively modified version of the double concentric tube heat exchanger as an intermediate tube adds some advantages over the double tube heat exchangers in that it is larger tube surface area heat transfer per unit of length.  In the present study, the triple tube heat exchanger is further modified by inserting helical baffle over the surface of one of the tubes and observed turbulence flow which may lead to high heat transfer rates between the fluids of heat exchanger. Further, the Reynolds number, Nusselt number, friction factor of the flow at different mass flow rates of the hot fluid while keeping a constant mass flow rate of cold and normal temperature fluids were calculated. It was found that as the mass flow rate of the fluid increases the Reynolds number increases, the turbulence in the flow will increase which will cause the intermixing of the fluid, higher the rate of intermixing, more will be the heat transfer of the system.  


Author(s):  
Xiao Qi ◽  
Ke Hanbing ◽  
Zhao Zhenxing ◽  
Li Yongquan ◽  
Liao Mengran

Supercritical CO2 (S-CO2) Brayton cycle has been identified as a promising power conversion method for the next generation of nuclear reactors due to its high efficiency and compactness. The heat exchanger is one of the most important components for S-CO2 Brayton cycle, and the printed circuit heat exchanger (PCHE) is supposed to be one of the promising candidates for the heat exchangers in S-CO2 Brayton cycle. It should be noted that the fluid maldistribution would induce heat transfer deterioration, especially for heat exchangers with micro- or mini-scale channels like PCHE. The thermal-physical properties of S-CO2 change violently during the heat transfer process, which makes the flow inside PCHE more complex. In this paper, the distribution of S-CO2 flow inside PCHE would be studied by 2-D CFD simulations. For the working fluids with constant properties, the flow nonuniformity increases with the mass flow rate. For the working fluid with S-CO2, the thermal-physical properties change significantly with temperature, and there exist a minimum value in the flow nonuniformity-mass flow rate curves (1.64 × 105 ≤ Rein ≤ 1.31 × 106). Insertion of baffles at manifolds could significantly improve the flow distribution uniformity and reduce the pressure drop. And it has been found that insertion of baffles at the collecting manifold has better performance compared with that at the distributing manifold or both.


2017 ◽  
Vol 16 (05n06) ◽  
pp. 1750020 ◽  
Author(s):  
S. Nallusamy ◽  
N. Manikanda Prabu

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.


2021 ◽  
Vol 309 ◽  
pp. 01011
Author(s):  
R Elakkiyadasan ◽  
Kumar P Manoj ◽  
M Subramanian ◽  
N Balaji ◽  
M Karthick ◽  
...  

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.


2019 ◽  
Vol 8 (3) ◽  
pp. 4442-4449

In this research work, the design of pipe in pipe, shelland-tube and combined heat exchanger (previously mentioned types were combined to consider as one unit) has been made. These three heat exchangers have been utilized for two kinds of flows i.e., parallel as well counter flow types individually. The design of combined heat exchanger takes been proposed with the idea of increasing the heat transfer area and to understand the behavior of various parameters involved by comparing with the individual heat exchangers. 75:25 aqueous Ethylene Glycols, have been used as the working fluid in all three heat exchangers of counter as well parallel flow conditions. Total quantity of working fluid is 12 liters, in which 6liters of fluid is used as cold fluid and the other half is used as hot fluid. As a result, overall heat transfer coefficient (U) has been increased with increase of mass flow rate. Highest overall heat transfer coefficient value observed as 1943w/m2 -k at highest mass flow rate (within the considerations of this work) of 0.145 kg/s. The highest decrement in LMTD recorded for 0.0425 to 0.145 increase of mass flow rate is 49.32% in shell-and-tube heat exchanger of parallel flow arrangement. The highest effectiveness is observed for pipe in pipe counter flow heat exchanger case, which is 0.39 at a mass flow rate of 0.145kg/s.


2015 ◽  
Vol 37 ◽  
pp. 199
Author(s):  
Ali Mahrooghi ◽  
Mohammad Moghiman

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.


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