An Experimental Study of Condensate Retention on the Air Side of Flat-Tube Heat Exchangers

2010 ◽  
Author(s):  
Deep Gupta ◽  
Young-Gil Park ◽  
Anthony M. Jacobi
Keyword(s):  
Heat Exchangers ◽  
Qualitative Evaluation ◽  
Side Surface ◽  
Air Cooling ◽  
Robust Solution ◽  
Flat Tube ◽  
Compact Heat Exchangers ◽  
Drainage Channels ◽  
Retention Characteristics ◽  
Condensed Water

Condensate on the air-side surface of flat-tube air-cooling heat exchangers can result in several adverse effects on the overall thermal hydraulic performance. In order to enhance the performance of compact heat exchangers under wet-surface conditions, promoting the drainage of condensed water is critical. Drainage channels on tube walls might provide a robust solution to promote condensate drainage from compact heat exchangers. A quantitative and qualitative evaluation of the effectiveness of drainage channels on the condensate retention characteristics of compact flat-tube louver-fin heat exchangers is presented. Various geometries of drainage channels are engraved on the surrogate tubes in contact with fin stock. Two fin designs are tested using dynamic dip testing method and a small wind tunnel. The data from the quantitative results and the visualization tests clearly show that the drainage channels reduce the condensate retention for one of the fin designs. The results also provide a comparison between drainage channels based on their geometry and dimensions.

Dynamic dip testing as a method to assess the condensate drainage behavior from the air-side surface of compact heat exchangers

2005 ◽  
Vol 29 (8) ◽  
pp. 957-970 ◽  
Author(s):  
Yongfang Zhong ◽  
Arindom Joardar ◽  
Zhongping Gu ◽  
Young-Gil Park ◽  
Anthony M. Jacobi
Keyword(s):  
Heat Exchangers ◽  
Side Surface ◽  
Compact Heat Exchangers

scholarly journals An experimental investigation on air-side performances of finned tube heat exchangers for indirect air-cooling tower

2014 ◽  
Vol 18 (3) ◽  
pp. 863-874 ◽  
Author(s):  
Xueping Du ◽  
Yantao Yin ◽  
Min Zeng ◽  
Pengqing Yu ◽  
Qiuwang Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling Tower ◽  
Finned Tube ◽  
Air Cooling ◽  
Flat Tube ◽  
Tube Heat Exchanger ◽  
Air Inlet ◽  
Oval Tube

A tremendous quantity of water can be saved if the air cooling system is used, comparing with the ordinary water-cooling technology. In this study, two kinds of finned tube heat exchangers in an indirect air-cooling tower are experimentally studied, which are a plain finned oval-tube heat exchanger and a wavy-finned flat-tube heat exchanger in a cross flow of air. Four different air inlet angles (90?, 60 ?, 45?, and 30?) are tested separately to obtain the heat transfer and resistance performance. Then the air-side experimental correlations of the Nusselt number and friction factor are acquired. The comprehensive heat transfer performances for two finned tube heat exchangers under four air inlet angles are compared. For the plain finned oval-tube heat exchanger, the vertical angle (90?) has the worst performance while 45? and 30? has the best performance at small ReDc and at large ReDc, respectively. For the wavy-finned flat-tube heat exchanger, the worst performance occurred at 60?, while the best performance occurred at 45? and 90? at small ReDc and at large ReDc, respectively. From the comparative results, it can be found that the air inlet angle has completely different effects on the comprehensive heat transfer performance for the heat exchangers with different structures.

Numerical Evaluation of Fin Performance Under Dehumidifying Conditions

2007 ◽  
Vol 129 (10) ◽  
pp. 1395-1402 ◽  
Author(s):  
G. Comini ◽  
C. Nonino ◽  
S. Savino
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Exchangers ◽  
Numerical Evaluation ◽  
Energy Equation ◽  
Air Cooling ◽  
The Finite Element Method ◽  
Moist Air ◽  
Compact Heat Exchangers ◽  
Coupled Problem

A numerical model of moist air cooling in compact heat exchangers is presented. The model requires the solution of a coupled problem, since interface temperatures, obtained from the solution of the energy equation in adjacent fluid and solid regions, are used to set the appropriate boundary conditions for the transport equation of water vapor in moist air. The approach is completely general, even if the finite-element method is used for the simulations reported in the paper. The numerical results are favorably compared with the corresponding experimental results concerning the rectangular and wavy fins under dehumidifying conditions.

NUMERICAL EVALUATION OF THERMO-HYDRAULIC PERFORMANCE IN FIN-AND-TUBE COMPACT HEAT EXCHANGERS WITH DIFFERENT TUBE CROSS-SECTIONS

2016 ◽  
Vol 78 (8-4) ◽  
Author(s):  
Ahmadali Gholami ◽  
Mazlan Abdul Wahid ◽  
Hussein A. Mohammed ◽  
A. Saat ◽  
M.F. Mohd Yasin ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
Circular Tube ◽  
Hydraulic Performance ◽  
Flat Tube ◽  
Compact Heat Exchangers ◽  
Average Area ◽  
Flat Tubes ◽  
Goodness Factor ◽  
Circle Tube ◽  
Oval Tube

This study examined numericallythe Thermal-hydrodynamic properties of airflow in the fin-and-tube compact heat exchangers (FTCHEs) with considering different shapes of tubes in lowReynoldsnumbers. The influence of applying flat, oval and circular tube adjustments on the thermal and hydraulic characteristics of air flow were analyzed on the in-line tube arrangements. Establishing standard conditions, the study compared different geometries based on circular tubes of 10.459 mm diameter tubes with 25.4 mm longitudinal pitches and 25.4 mm transverse pitches. The other geometries of tubes were assumed in a stable and constant state preparing the same heat transfer surface area per unit volume as that of the nominal case. The results showed that the FTCHE with flat tubes gives the best area goodness factor (j/f) with in a certainrange of Reynoldsnumbers. In addition, FTCHE with flat tubes shown the best thermo-hydraulic performance and a significant augmentation of up to 10.83% and 35.63% in the average area goodness factor achieved accompanied by a decrease in the average friction factor of 17.02% and 43.41% in the flat tube case compared to the oval and circle tube shapes, respectively. It is concluded that the average area goodness factorfor the oval tube is about 25.04% higher than that of the circular tube, while the average friction factor for the oval tube is about 26.9% lower than that of the circular tube. This means that the flat tube has a better-combined thermal–hydraulic performance than the oval and circle tube.

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