Heat transfer and pressure drop characteristics of 3-D finned tube heat exchanger in ash-laden flue gas

Author(s):  
Min Cheng ◽  
Zi-yong Chen ◽  
Qiang Liao ◽  
Yu-heng Gu ◽  
Yu-dong Ding
2017 ◽  
Author(s):  
In-Cheol Chu ◽  
Kil Won Park ◽  
Woo Jin Jeon ◽  
Hyo Seong Seol ◽  
Tae-Soon Kwon ◽  
...  

2020 ◽  
Vol 15 ◽  

A three dimensional numerical study has been conducted on finned-tube heat exchanger with multiple rows of tubes using ANSYS (Fluent). The objective of this study is to numerically investigate finned tube heat exchanger with different type of tubes such as circular, elliptical and rectangular tubes. As circular tubes has much pressure drop so elliptical and rectangular tubes has been introduced in order to reduce pressure drop. As well as heat transfer has also been examined. The finite volume based CFD code ANSYS Fluent 16.2 is used to calculate the flow and temperature fields and by applying SIMPLEC algorithm. At low velocity of air and water, nothing significant occurred for the combination of tubes. At high velocity in maximum tube combination there was heat transfer (HT) enhancement and pressure drop reduction when compared with circular tubes only in case of air. When the combinations of circular, elliptical and rectangular tubes has been compared with circular tube heat exchanger (CTHX) heat transfer reduces as well as pressure drop (PD) also reduces for air. In case of water vapor HT and PD behaves the same. When those combinations has been compared with elliptical tube HX, for air in some cases heat transfer remains same and on other case it increases. For pressure drop in case of air, in some cases it reduces and on other cases it reduces. For elliptical tube HX for the fluid water vapor HT and PD both remains same or reduces. This work has not been with conducted any numerical simulation on rectangular Heat exchanger reason behind it there isn’t any existence of this kind of heat exchanger. However, it could be numerically conducted to examine the results between those combination and rectangular heat exchanger.


Author(s):  
Bruno F. Pussoli ◽  
Jader R. Barbosa ◽  
Luciana W. da Silva ◽  
Massoud Kaviany

We present an experimental evaluation of the peripheral finned-tube heat exchanger. In this novel compact evaporator geometry, the air-side is composed by an arrangement of open-pore cells formed by radial fins whose bases are attached to the tubes and whose tips are connected to peripheral fins. Each fin arrangement is made up of six radial fins and six peripheral fins forming a hexagon-like structure. The air-side fin configuration is composed of three levels of fin arrangement, each characterized by the length of radial fin and mounted with a 30° offset from its neighboring level. Experimental data on the air-side heat transfer and pressure drop were generated in an open-loop wind tunnel calorimeter. A one-dimensional theoretical model based on the theory of porous media has also been developed to predict the thermal-hydraulic behavior of the heat exchanger. The model incorporates the actual fin geometry into the calculation of the air-side porosity. The air-side permeability is calculated according to the Kozeny-Carman model with the particle diameter definition due to Whitaker and the friction factor correlation due to Ergun. The model overpredicts the air-side thermal conductance by less than 15% for air flow rates higher than 14 L/s. The air-side pressure drop is underpredicted by the model, but still within the limits encountered in the literature. The analysis is complemented with an entropy generation minimization analysis in order to demonstrate the procedure for obtaining an optimized configuration of the heat exchanger.


2016 ◽  
Vol 37 (2) ◽  
pp. 3-22 ◽  
Author(s):  
Pavan Kumar Konchada ◽  
Vinay Pv ◽  
Varaprasad Bhemuni

AbstractThe presence of nanoparticles in heat exchangers ascertained increment in heat transfer. The present work focuses on heat transfer in a longitudinal finned tube heat exchanger. Experimentation is done on longitudinal finned tube heat exchanger with pure water as working fluid and the outcome is compared numerically using computational fluid dynamics (CFD) package based on finite volume method for different flow rates. Further 0.8% volume fraction of aluminum oxide (Al2O3) nanofluid is considered on shell side. The simulated nanofluid analysis has been carried out using single phase approach in CFD by updating the user-defined functions and expressions with thermophysical properties of the selected nanofluid. These results are thereafter compared against the results obtained for pure water as shell side fluid. Entropy generated due to heat transfer and fluid flow is calculated for the nanofluid. Analysis of entropy generation is carried out using the Taguchi technique. Analysis of variance (ANOVA) results show that the inlet temperature on shell side has more pronounced effect on entropy generation.


1990 ◽  
Vol 112 (1) ◽  
pp. 64-70 ◽  
Author(s):  
S. A. Idem ◽  
A. M. Jacobi ◽  
V. W. Goldschmidt

The effects upon the performance of an air-to-water copper finned-tube crossflow heat exchanger due to condensation on the outer surface are considered. A four-tube, two-pass heat exchanger was tested over a Reynolds number range (based on hydraulic diameter) from 400 to 1500. The coil was operated both in overall parallel and overall counterflow configurations. Convective heat and mass transfer coefficients are presented as plots of Colburn j-factor versus Reynolds number. Pressure losses are, similarly, presented as plots of the friction factor versus Reynolds number. Enhancement of sensible heat transfer due to the presence of a condensate film is also considered.


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