Study of thermal effectiveness and its relation with NTU in shell and helically coiled tube heat exchangers

Alimoradi, Ashkan

doi:10.1016/j.csite.2017.01.003

Cited by 46 publications

(12 citation statements)

References 15 publications

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“…Based on the mathematical model formed, i.e., equation ( 12), it was known that Prantld number did not influence the heat transfer in the vertical tubular baffle internal reboiler because the process was carried out at the same temperature. As stated by (Alimoradi, 2017), the viscosity and thermal conductivity of fluid are influenced by temperature. In addition, a difference in the tube diameter and mass density of the material brought a significant difference in the convective heat transfer coefficient.…”

Section: Effect Of Differences In Diameter Tube Height and Concentrat...mentioning

confidence: 99%

“…An increase in the Reynold number can increase the overall heat transfer coefficient (Putra et al, 2013 andFouda, et.al., 2018). An increase in the heat transfer coefficient in a heat exchanger is related to geometric parameters and Reynold number (Ghorbani et al, 2010 andAlimoradi, 2017). An addition of twisted tape in the heat transfer tube (Padmanabhan et 2021) and fins on a helical coil (Tuncer et al, 2021) can also increase the heat transfer coefficient.…”

Section: Effect Of Differences In Diameter Tube Height and Concentrat...mentioning

confidence: 99%

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Heat Transfer Characteristics in Vertical Tubular Baffle Internal Reboiler through Dimensional Analysis

Susmiati¹,

Purwantana²,

Bintoro³

et al. 2022

IJTech

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Heat transfer in shell and tube heat exchangers is in general described in terms of the relationships of Nuselt, Prandtl, and Reynold dimensionless numbers. One of the parameters of heat exchanger performance is convective heat transfer coefficient (h), and mathematical model can predict it. This study aimed to find out the relationship of the parameters that affected the performance of vertical tubular baffle internal reboiler during ethanol distillation. The mathematical model was developed by a dimensional analysis with the π-Buckingham method. Several influencing parameters during the distillation process were identified to develop a mathematical model. The study was carried out on the distillation process of low-concentration ethanol, i.e., 10%, 20%, 30% using internal reboilers with different tube sizes, i.e., diameters of 1.27 cm, 2.54 cm, 3.81 cm and height of 4 cm, 6 cm, 8 cm, to obtain the value of h observation. Based on the results of the study, a heat transfer model was obtained, i.e., 𝑵𝒖 = 𝟏𝟒𝟓𝟐. 𝟐𝟗 𝑹𝒆 𝟎.𝟑𝟓𝟕 ( 𝑫 𝑳

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Section: Effect Of Differences In Diameter Tube Height and Concentrat...mentioning

confidence: 99%

Section: Effect Of Differences In Diameter Tube Height and Concentrat...mentioning

confidence: 99%

Heat Transfer Characteristics in Vertical Tubular Baffle Internal Reboiler through Dimensional Analysis

Susmiati¹,

Purwantana²,

Bintoro³

et al. 2022

IJTech

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“…The effects of operational and geometrical parameters on the thermal effectiveness of shell and helically coiled tube heat exchangers ware investigated through numerical methods and experimental validation. For the same values of NTU and C r , the effectiveness of shell and coiled tube heat exchangers was on average 12.6% less than the effectiveness of the parallel flow heat exchangers and this difference was approximately constant [14].…”

Section: Introductionmentioning

confidence: 95%

The Local Distribution of Temperatures and Entropy Generation Rate in an Ideal Counterflow Heat Exchanger

Dong¹,

Du²

2021

Coatings

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The process of heat exchange between two fluids of different temperatures and separated by a solid wall occurs in many engineering applications. Log mean temperature difference and effectiveness-NTU methods are widely used to assist in the design of heat exchangers. However, the two methods focus on overall analysis and cannot show the local temperature distributions. This paper obtains the mathematical solutions to the temperature profiles in an ideal counterflow heat exchanger. The aim of this research is to explain the phenomenon called the “entropy generation paradox”, which indicates a discrepancy between effectiveness and optimal entropy generation. The theoretical analysis reveals that the temperature curves are exponential functions when the heat capacity rates of the two streams are different; otherwise, the curves are linear functions. A heat exchanger is demonstrated to draw the temperature profiles under different working conditions. Local entropy generation rates are determined by the ratio of local stream temperatures in the form of a hook function. To realize a certain heat duty, there are many stream flow rate couples, and each couple results in a different entropy generation profile and obtains a corresponding total entropy generation. The helical steam generator of a high-temperature gas-cooled reactor is analyzed in this article and the principle of equipartition of entropy generation is confirmed. This principle indicates that, among the many working conditions to achieve a certain heat duty, a heat exchanger characterized by a nearly constant entropy production gives the best second law efficiency possible in order to achieve the best energy conversion.

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“…Heat transfer enhancement techniques are classified as the -Passive Methods, Active Methods, and Compound Methods. [8][9][10] These methods are commonly used in areas such as process industries, heating and cooling in evaporators, air-conditioning equipment, refrigerators, radiators for space vehicles, automobiles, etc. The rate of heat transfer can be increased passively by increasing the surface area, roughness, and by changing the boundary conditions.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Design and Analysis on The Helically Coiled Tube Heat Exchanger By Providing Fins

Kumar¹,

Mohan²

2020

Smart Moves Journal Ijoscience

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Heat exchangers are an essential part in an assortment of mechanical settings, for example, cooling frameworks, force plants, refineries, and in this way ceaseless endeavor are made to expand their heat transfer efficiencies. Optimize design of helical coil heat exchanger by using fins and the Compare pressure & temperature by conventional design. The final outcome of the study increase the total heat transfer rate inside the domain. And increase the pressure drop inside the domain. The water outlet temperature decrease up to 315k and cold outlet temperature increase up to 320 k. and total pressure drop increase with the temperature increases. Finally the CFD data were compared with previous data the total pressure drop increase up to 0.65 bar for case-2.the overall efficiency of the system incites up to 5% to 6%.

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Study of thermal effectiveness and its relation with NTU in shell and helically coiled tube heat exchangers

Cited by 46 publications

References 15 publications

Heat Transfer Characteristics in Vertical Tubular Baffle Internal Reboiler through Dimensional Analysis

Heat Transfer Characteristics in Vertical Tubular Baffle Internal Reboiler through Dimensional Analysis

The Local Distribution of Temperatures and Entropy Generation Rate in an Ideal Counterflow Heat Exchanger

Optimizing Design and Analysis on The Helically Coiled Tube Heat Exchanger By Providing Fins

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