Somchai Industry Co.

Bangkok, Thailand

Somchai Industry Co.

Bangkok, Thailand
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Pongsoi P.,King Mongkut's University of Technology Thonburi | Pikulkajorn S.,Somchai Industry Co. | Wang C.-C.,National Chiao Tung University | Wongwises S.,King Mongkut's University of Technology Thonburi | Wongwises S.,Academy of Science
International Journal of Heat and Mass Transfer | Year: 2012

The air-side performance of crimped spiral fin and tube heat exchangers at high Reynolds number (3000-13,000) is investigated in this study. The test heat exchangers have a new type of multipass parallel and counter cross-flow water flow arrangement which is a combination of parallel cross-flow and counter cross-flow. The test samples are made from copper and aluminium with different number of tube rows (Nrow = 2, 3, 4 and 5). The effects of number of tube rows and fin material on the heat transfer and friction characteristics are studied. The results show that no significant effect for either number of tube rows or fin materials on the heat transfer performance is found at high Reynolds number. In addition, the correlation of the air-side performances of this type of the heat exchangers at high Reynolds number is developed for industrial applications. © 2011 Elsevier Ltd. All rights reserved.


Pongsoi P.,King Mongkut's University of Technology Thonburi | Pikulkajorn S.,Somchai Industry Co. | Wang C.-C.,National Chiao Tung University | Wongwises S.,King Mongkut's University of Technology Thonburi
International Journal of Heat and Mass Transfer | Year: 2011

This study investigates the effect of fin pitches and fin materials on the air-side performance of crimped fin-and-tube heat exchangers in the range of high Reynolds numbers (4000-13000). The test samples are made from copper and aluminium with different fin pitches (fp = 3.2, 4.2 and 6.2 mm). It is found that the proposed simple average effectiveness equation from the pure counter and parallel circuitry arrangement can well represent the effectiveness-NTU relationship for the current z-shape arrangement. The experimental results reveal that the fin pitch casts insignificant effect on the heat transfer characteristics (Colburn j factor). However, a detectable rise of the friction factor is seen when the fin pitch is increased to fp = 6.2 mm. On the other hand, the effect of fin material on the airside performance is negligible. © 2010 Elsevier Ltd. All rights reserved.


Pongsoi P.,King Mongkut's University of Technology Thonburi | Pikulkajorn S.,Somchai Industry Co. | Wongwises S.,King Mongkut's University of Technology Thonburi | Wongwises S.,Academy of Science
International Journal of Heat and Mass Transfer | Year: 2012

This study conducted experiments on the optimized fin pitch for crimped spiral fin-and-tube heat exchangers. The experiments covered a size range of 2.4-6.5 mm, which is the manufacturing limitation for this kind of fin. The water-flow arrangement used in this experiment combined the parallel cross-flow and the counter cross-flow in a two-row configuration. Ambient air was used as the working fluid on the air-side, and hot water was used on the tube-side. The effects of fin pitches on the heat transfer coefficient and pressure drop characteristics were studied. The results clearly showed that the convective heat transfer coefficient (h o) for a fin pitch of 2.4 mm is relatively low compared with that of other fin pitches with the same air frontal velocity. Using larger fin pitches (i.e., 4.2, 6.2, and 6.5 mm) resulted in negligible differences in the pressure drop. Moreover, this work introduces the parameter of three performances indexes, which can be expressed as the ratio of the desired output to the required input, for optimization purposes. Due to the difference in optimum fin pitch obtained by these performance indexes, an intersection analysis was conducted. The results indicated that the optimum fin pitch is 4.2 mm for this work, which could be valuable for the effective design for industrial thermal-system applications. © 2012 Elsevier Ltd. All rights reserved.


Pongsoi P.,King Mongkut's University of Technology Thonburi | Pikulkajorn S.,Somchai Industry Co. | Wongwises S.,King Mongkut's University of Technology Thonburi | Wongwises S.,Academy of Science
Heat Transfer Engineering | Year: 2012

This study conducted experiments on the air-side performance of novel L-footed spiral fin-and-tube heat exchangers that were faced with airflow at high Reynolds numbers (3500-13,000). The examined heat exchangers have a multipass parallel-and-counter cross-flow type of water flow arrangement. This flow arrangement is a combination of the parallel cross-flow and the counter cross-flow. This type of water flow arrangement may be the best fit for the reverse-flow system, because it can provide constant heat-exchange effectiveness for every flow reversal direction at the same airflow rate. Ambient air was used as a working fluid on the air side and hot water for the tube side. This way the effect of the number of tube rows on the heat transfer and friction characteristics of L-footed spiral fin-and-tube heat exchangers was clearly observed. The effect of the fin's outside diameter on the pressure drop was also studied. The results show that the number of tube rows has no significant effect on the air-side heat transfer or on friction characteristics at high Reynolds numbers. However, the fin's outside diameter shows a significant effect on the pressure drop. The pressure drop increases as the fin's outside diameter increases for the same number of tube rows. © 2012 Copyright Taylor and Francis Group, LLC.


Pongsoi P.,King Mongkut's University of Technology Thonburi | Pikulkajorn S.,Somchai Industry Co. | Wongwises S.,King Mongkut's University of Technology Thonburi
International Journal of Heat and Mass Transfer | Year: 2014

In the present study, an attempt has been made to summarize and analyze the results of an examination of the air-side performance of spiral (or helical) fin-and-tube heat exchangers. Currently, the spiral fin-and-tube heat exchanger is a favored type of heat exchanger for the waste heat recovery unit (WHRU), a kind of economizer system. The present paper is broadly divided into an experimental section and numerical and simulation sections. A significant fraction of the papers herein reviewed pertains to the effect of fin configurations, tube arrangements, operating conditions, and other factors on the air-side performance of the spiral fin-and-tube heat exchangers. Approximately 40 published articles related to spiral fin-and-tube heat exchangers are briefly described. Moreover, the air-side performance correlations of spiral fin and circular fin-and-tube heat exchangers are compiled into this work for practical industrial applications. © 2014 Elsevier Ltd. All rights reserved.


Kiatpachai P.,King Mongkut's University of Technology Thonburi | Pikulkajorn S.,Somchai Industry Co. | Wongwises S.,King Mongkut's University of Technology Thonburi
International Journal of Heat and Mass Transfer | Year: 2015

Abstract Heat exchanger is a basic component used in thermal processes such as industrial fluid heating, household appliances, waste heat recovery units (WHRU), etc. Presently, the spiral fin-and-tube heat exchanger is used as a favored type of heat exchanger for the waste heat recovery unit system, i.e., the economizer heat exchanger. The study investigates the effect of fin pitches on the air-side performance of serrated welded spiral fin-and-tube heat exchangers having Z-shape flow arrangement and the number of tube rows of 2 in range of high Reynolds numbers (4000-15,000). The test samples are made from steel (iron) with different fin pitches of 3.6, 4.2, and 6.2 mm. The experimental results reveal that the fin pitch has a significant effect on the air-side performance. It is confirmed that the fin pitch of 3.6-6.2 mm has the same trend in heat transfer coefficient at the tested condition. For f-friction factor, a detectable rise of the friction factor is found when the fin pitches increase to 6.2 mm. Moreover, the air-side performance correlations of serrated welded spiral finned tube heat exchangers are proposed for practical industrial applications. The proposed air-side performance correlation describes 100% for j-Colburn factor and f-friction factor within 10%. © 2015 Elsevier Ltd.


Pongsoi P.,King Mongkut's University of Technology Thonburi | Promoppatum P.,King Mongkut's University of Technology Thonburi | Pikulkajorn S.,Somchai Industry Co. | Wongwises S.,King Mongkut's University of Technology Thonburi | Wongwises S.,Academy of Science
International Journal of Heat and Mass Transfer | Year: 2013

The purpose of this experimental investigation is to investigate the effects of fin pitch (i.e., fp of 2.4, 3.2, and 4.2 mm) on the air-side heat transfer performance and frictional characteristics of L-footed spiral fin-and-tube heat exchangers at high Reynolds numbers (Redc) of 4000-15,000. A determinant of the parallel cross-flow and the counter cross-flow is the flow arrangement of the test heat exchangers. Ambient air and hot water are used as a working fluid on the air- and the tube-side, respectively. The results indicate that the air-side heat transfer coefficient and Colburn factor are independent of fin pitch. However, fin pitch does have an influential effect on the average heat transfer rate, pressure drop, and friction factor. In terms of industrial applications, the correlation of the Colburn factor and friction factor are proposed for practical applications. © 2012 Elsevier Ltd. All rights reserved.

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