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Condensation heat transfer and pressure drop characteristics of Isobutane in horizontal channels with twisted tape inserts

journal contribution
posted on 2023-06-07, 07:23 authored by Hadi Ahmadi Moghaddam, Alireza Sarmadian, Amirmasoud Asnaashari, Hossein Ahmadi Nejad Joushani, Mohammad Saidul Islam, Suvash C Saha, Golara Ghasemi, Maziar Shafaee
The enhancement of heat transfer rate in heat exchangers has been considered a major concern. In this research, the impacts of inserting twisted tapes in horizontal two-phase flow heat exchangers are discussed, and different values of vapor qualities (in the range of 0.1 to 0.7) and mass velocities (in the range of 119 to 367 kgm-2s-1) are considered during forced convective condensation of R600a (Isobutane). The test case is a pipe made from copper with an inner diameter of 8.1 mm and a length of 1000 mm. Furthermore, three twisted tape inserts with various twist ratios (defined as the ratio of the twisted tape pitch to the test pipe inner diameter) of 4, 10, and 15 are used. The results illustrated that installing twisted tapes results in the increment of pressure drops and the rate of heat transfer in comparison to the smooth case. Furthermore, the pressure drops and heat transfer rates augment as the refrigerant mass velocity and vapor quality increase. Depending on the inserts type and operating conditions, the performance factor (a criterion to assess the performance modification compared to the primary test case) between 0.39 to 1.05 was obtained. It was also observed that there exists an optimum amount of the refrigerant mass velocity at which the performance factor is higher. Results showed that generally using twisted tapes in heat exchangers is not instrumental unless when the main concern is to improve the heat transfer rate or when the augmented power consumed by pump can be justified.

History

Publication status

  • Published

File Version

  • Accepted version

Journal

International Journal of Refrigeration

ISSN

0140-7007

Publisher

Elsevier

Department affiliated with

  • Engineering and Design Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2020-07-06

First Open Access (FOA) Date

2020-07-06

First Compliant Deposit (FCD) Date

2020-07-06

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