The effects of twisted strips with different length on heat transfer and pressure drop in concentric heat exchanger

Zeki Argunhan; Cengiz Yıldız; Emin El

Makale detayları

The effects of twisted strips with different length on heat transfer and pressure drop in concentric heat exchanger

Yazarlar:

Zeki Argunhan | Cengiz Yıldız | Emin El

Yayıncı:

Bitlis Eren University

Ana Başlıklar:

Energy Generation | Conversion and Storage (Excl. Chemical and Electrical)

Dergi:

Bitlis Eren University Journal of Science and Technology Vol.15 Issue 1, pp.99-111

Belge Tipi:

Makale

Yayın Tarihi:

6/2025

Belge Dili:

İngilizce

Document ID (Org No.):

2001353581

pISSN:

2146-7706

Anahtar kelimeler:

Özet:

 This study investigated the use of twisted strips as passive turbulators to improve heat transfer efficiency in concentric heat exchangers. In the experiments, four different lengths of twisted strips were designed l  0.25 m, 0.5 m, 0.75 m, and 1 m and their performance was evaluated in a system with air and water fluids. The effects of twisted strips on heat transfer and pressure drops are investigated in both parallel and countercurrent flow patterns, and the results are analyzed in terms of Nusselt and Reynolds numbers. The results indicated that tubes using twisted strips achieved significant increases in the heat transfer coefficient compared to straight tubes. The highest increase in heat transfer performance reached 78 when the length of the twisted strip was lL1. The Nusselt number increased by a factor of 1.2 to 1.8, depending on the length of the twisted strips. The shortest strip length lL0.25 resulted in the lowest heat transfer performance. However, these improvements were accompanied by significant increases in pressure drop; for full-length strips, the pressure drop increased by nearly 100. The pressure drop increased slightly as the Reynolds number increased. The swirling flow generated by the twisted ribbons plays an important role in increasing the heat transfer. Despite the increases in pressure drops, the energy loss is negligible compared to the heat transfer gain achieved. In conclusion, the length ratio of the twisted strips significantly affects the thermal performance of the heat exchanger while increasing the pressure losses. These findings demonstrate the effectiveness of twisted strips as passive turbulators.

 This study investigated the use of twisted strips as passive turbulators to improve heat transfer efficiency in concentric heat exchangers. In the experiments, four different lengths of twisted strips were designed l  0.25 m, 0.5 m, 0.75 m, and 1 m and their performance was evaluated in a system with air and water fluids. The effects of twisted strips on heat transfer and pressure drops are investigated in both parallel and countercurrent flow patterns, and the results are analyzed in terms of Nusselt and Reynolds numbers. The results indicated that tubes using twisted strips achieved significant increases in the heat transfer coefficient compared to straight tubes. The highest increase in heat transfer performance reached 78 when the length of the twisted strip was lL1. The Nusselt number increased by a factor of 1.2 to 1.8, depending on the length of the twisted strips. The shortest strip length lL0.25 resulted in the lowest heat transfer performance. However, these improvements were accompanied by significant increases in pressure drop; for full-length strips, the pressure drop increased by nearly 100. The pressure drop increased slightly as the Reynolds number increased. The swirling flow generated by the twisted ribbons plays an important role in increasing the heat transfer. Despite the increases in pressure drops, the energy loss is negligible compared to the heat transfer gain achieved. In conclusion, the length ratio of the twisted strips significantly affects the thermal performance of the heat exchanger while increasing the pressure losses. These findings demonstrate the effectiveness of twisted strips as passive turbulators.

 This study investigated the use of twisted strips as passive turbulators to improve heat transfer efficiency in concentric heat exchangers. In the experiments, four different lengths of twisted strips were designed l  0.25 m, 0.5 m, 0.75 m, and 1 m and their performance was evaluated in a system with air and water fluids. The effects of twisted strips on heat transfer and pressure drops are investigated in both parallel and countercurrent flow patterns, and the results are analyzed in terms of Nusselt and Reynolds numbers. The results indicated that tubes using twisted strips achieved significant increases in the heat transfer coefficient compared to straight tubes. The highest increase in heat transfer performance reached 78 when the length of the twisted strip was lL1. The Nusselt number increased by a factor of 1.2 to 1.8, depending on the length of the twisted strips. The shortest strip length lL0.25 resulted in the lowest heat transfer performance. However, these improvements were accompanied by significant increases in pressure drop; for full-length strips, the pressure drop increased by nearly 100. The pressure drop increased slightly as the Reynolds number increased. The swirling flow generated by the twisted ribbons plays an important role in increasing the heat transfer. Despite the increases in pressure drops, the energy loss is negligible compared to the heat transfer gain achieved. In conclusion, the length ratio of the twisted strips significantly affects the thermal performance of the heat exchanger while increasing the pressure losses. These findings demonstrate the effectiveness of twisted strips as passive turbulators.

 This study investigated the use of twisted strips as passive turbulators to improve heat transfer efficiency in concentric heat exchangers. In the experiments, four different lengths of twisted strips were designed l  0.25 m, 0.5 m, 0.75 m, and 1 m and their performance was evaluated in a system with air and water fluids. The effects of twisted strips on heat transfer and pressure drops are investigated in both parallel and countercurrent flow patterns, and the results are analyzed in terms of Nusselt and Reynolds numbers. The results indicated that tubes using twisted strips achieved significant increases in the heat transfer coefficient compared to straight tubes. The highest increase in heat transfer performance reached 78 when the length of the twisted strip was lL1. The Nusselt number increased by a factor of 1.2 to 1.8, depending on the length of the twisted strips. The shortest strip length lL0.25 resulted in the lowest heat transfer performance. However, these improvements were accompanied by significant increases in pressure drop; for full-length strips, the pressure drop increased by nearly 100. The pressure drop increased slightly as the Reynolds number increased. The swirling flow generated by the twisted ribbons plays an important role in increasing the heat transfer. Despite the increases in pressure drops, the energy loss is negligible compared to the heat transfer gain achieved. In conclusion, the length ratio of the twisted strips significantly affects the thermal performance of the heat exchanger while increasing the pressure losses. These findings demonstrate the effectiveness of twisted strips as passive turbulators.

Makale detayları

The effects of twisted strips with different length on heat transfer and pressure drop in concentric heat exchanger

Yazarlar:

Zeki Argunhan | Cengiz Yıldız | Emin El

Yayıncı:

Bitlis Eren University

Ana Başlıklar:

Energy Generation | Conversion and Storage (Excl. Chemical and Electrical)

Dergi:

Bitlis Eren University Journal of Science and Technology Vol.15 Issue 1, pp.99-111

Belge Tipi:

Makale

Yayın Tarihi:

6/2025

Belge Dili:

İngilizce

Document ID (Org No.):

2001353581

pISSN:

2146-7706

Twisted Strips

Concentric Heat Exchanger

Heat transfer

Pressure Drop

Sayı

Makale detayları

The effects of twisted strips with different length on heat transfer and pressure drop in concentric heat exchanger

Yazarlar: Zeki Argunhan | Cengiz Yıldız | Emin El

Yayıncı: Bitlis Eren University

Ana Başlıklar: Energy Generation | Conversion and Storage (Excl. Chemical and Electrical)

Dergi: Bitlis Eren University Journal of Science and Technology Vol.15 Issue 1, pp.99-111

Belge Tipi: Makale

Yayın Tarihi: 6/2025

Belge Dili: İngilizce

Document ID (Org No.): 2001353581

pISSN: 2146-7706

Twisted Strips

Concentric Heat Exchanger

Heat transfer

Pressure Drop

Sayı

Yazarlar:

Zeki Argunhan | Cengiz Yıldız | Emin El

Yayıncı:

Bitlis Eren University

Ana Başlıklar:

Energy Generation | Conversion and Storage (Excl. Chemical and Electrical)

Dergi:

Bitlis Eren University Journal of Science and Technology Vol.15 Issue 1, pp.99-111

Belge Tipi:

Makale

Yayın Tarihi:

6/2025

Belge Dili:

İngilizce

Document ID (Org No.):

2001353581

pISSN:

2146-7706