Comparative Experimental Study and Performance Intensification of Heat Exchanger by 55° Corrugated Tube and Twisted Tape Inserts of Pitch Length 1.5

Abstract

Introduction

The document focuses on improving heat transfer performance in Double Pipe Heat Exchangers (DPHEs) by using twisted tape inserts and corrugated tubes, applying both passive and active techniques.

Key Concepts and Background

• Heat transfer occurs when two fluids at different temperatures exchange energy across a solid barrier.

• DPHEs are widely used due to their simple design and low cost, especially in industries like food, oil, and chemical processing.

• Improving heat transfer efficiency is essential for sustainable energy applications.

Enhancement Techniques

• Passive Methods: Change geometry or fluid properties (e.g., twisted tape, corrugations, grooves, nanoparticles).

• Active Methods: Involve external forces (e.g., bubble injection, electromechanical vibration, magnetic/electric stimulation).

  • Passive methods are simple but increase pressure drop.

  • Active methods are effective but costly and complex.

Study Focus

This study explores a novel approach combining passive techniques, specifically:

• Using corrugated tubes as turbulators.

• Incorporating twisted tape inserts to enhance mixing and reduce thermal resistance.

Experimental Setup

• Materials: Copper and steel tubes (plain and corrugated), twisted tape inserts.

• Test Conditions: Hot and cold fluid flow varied; key measurements include effectiveness, LMTD, NTU, and overall heat transfer coefficient.

• Tools: Various industrial-grade components (valves, pumps, heaters, etc.) in a controlled lab environment.

Findings

1. Twisted Tape Effects:

   • Lower twist ratios → higher Nusselt number (Nu) and efficiency.

   • Short-length tapes placed near the tube entrance improved heat transfer in laminar flow.

2. Tube Comparisons:

   • Corrugated tubes (especially copper) performed better than plain tubes.

   • Twisted tape inserts further enhanced heat transfer.

   • Best performance was observed in corrugated steel tubes with inserts in counter flow configuration.

3. Graphical Analysis (Highlights):

   • Graphs showed trends for effectiveness, LMTD, overall heat transfer coefficient, NTU, and heat transfer rate.

   • Across all metrics, counter flow arrangements outperformed parallel flow.

Conclusion

A straight steel tube and 55° corrugated steel tube heat exchanger was experimentally analyzed in the heat and mass transfer lab. Using parallel and counter flow configurations with and without insert, the mass flow rates of hot fluid inside and outside the tubes were changed. The heat exchanger\'s efficiency is significantly impacted by both the hot and cold-water flow rates. Efficacy gradually decreases when the mass flow rate of cold water is fixed at 45 LPH and the mass flow rate of hot water is increased. In all flow directions, straight steel tube is more effective than bent tube when used in parallel flow. The overall heat transfer coefficient rises as the mass flow rate of hot water does. It is reported that the maximum overall heat transfer occurs at a hot water mass flow rate of 75 LPH at 55° corrugated steel tube with insert counter flow. When the hot water flow rate varies and the cold-water flow rate is set at 45 LPH, the LMTD in a straight steel tube with parallel flow is at least 15 LPH. This experimental setup uses a cheap, straight heat exchanger tube. In the future, the material composition of the straight steel tube heat exchanger may alter in order to increase the heat exchanger\'s efficiency. It was discovered that the heat transfer rate increases with the volume flow rate of hot water in both the parallel and counterflow cases, with the counterflow case exhibiting a larger heat transfer rate than the parallel flow case. The steel tube with 55° corrugation with insert was found to have a higher rate of heat transmission than the other variants in both cases. Maximum heat transfer rate measured in a counterflow configuration in 55° 55° corrugated steel tube with insert was 636.43 Watt; this is 21.91% higher than the rate of parallel flow in a plain steel tube in counter flowand 24.58% higher than the rate of heat transfer in a parallel configuration. It refers to the corrugation in tubes, variance in the volume flow rate of hot fluid, and the rate of heat transfer on the relative direction of fluid motion. The counter flow configuration in a corrugated steeltube with insert was found to have the highest efficacy value0.676. This figure is more than the highest value of efficacy in counter flow arrangements for plain steel tubes and corrugated steel tubes without insert, by 22.49% and 17.18%, respectively. The highest total heat transfer coefficient of 571.88 W/m2K for a corrugatedsteel tube with insert was found to be 17.24% and 31.13% higher in a parallel flow arrangement than the maximum values for those two designs, respectively. It was discovered that when the volume flow rate of hot fluid increases, so does the value of the overall heat transfer coefficient. The corrugated steel tube in parallel flow arrangement with insert and the plane steel tube in with insert in parallel flow were found to have values 21.53% and 18.09% lesser than maximum respectively, the maximum value of LMTD, which was observed for the plain steel tube without insert at 22.52 C. It was discovered that when the volume flow rate of hot fluid increases, the value of LMTD also increases. The results showed that the initial value of NTU decreased as the volume flow rate of hot fluid up to 45 lph and it again increases from 45 lphThe lowest value of NTU was found to be 1.427 in the case of plane steel tube, which is 36.52% and 28.14% smaller than the values found in the corrugated steel tube with insert in parallel flow and the corrugated steel tube without insert, respectively.

References

[1] M. Kim, C. Han, C. Baek, Y. Kim, Int. Commun. Heat Mass Tran. 144 (2023) 106798. [2] Q. Hu, X. Qu, W. Peng, J. Wang, Int. J. Heat Mass Tran. 185 (2022) 122385. [3] W. Liao, S. Lian, Int. J. Therm. Sci. 185 (2023) 108036. [4] N. Mashoofi, S. Pourahmad, S.M. Pesteei, J. Mech. Eng. 48 (2018) 301–307. [5] M. Eid, M.N.M. Zubir, M.R. Muhamad, S.N. Kazi, S.M. Aznam, M.H. Rony, F.A. Ibrahim, M.S. Alam, R. Sadri, Phys. Fluids 35 (2023). [6] T.S. Mogaji, A.O. Olapojoye, E.T. Idowu, B. Saleh, J. Braz. Soc. Mech. Sci. Eng. 44 (2022) 90. [7] A. Khashaei, M. Ameri, S. Azizifar, M.H. Cheraghi, Int. Commun. Heat Mass Tran. 149 (2023) 107149. [8] A. W. Albanesi, K. D. Daish, B. Dally and R. C. Chin. [9] L. Karikalan, S. Baskar, N. Poyyamozhi, K. Negash, J. Nanomater. (2022) 2022. [10] B. Mehta, D. Subhedar, H. Panchal, Z. Said, J. Mol. Liq. (2022) 120034. [11] N.M. Maleki, S. Pourahmad, Int. Commun. Heat Mass Tran. 141 (2023) 106566. [12] N. Rehman, R. Mahmood, A.H. Majeed, M.R. Ali, A.S. Hendy, Case Stud. Therm. Eng. (2024) 104391. [13] V. Gosty, G. Srinivas, B.S. Babu, B.S. Goud, A.S. Hendy, M.R. Ali, Case Stud. Therm. Eng. (2024) 104368. [14] S.D. Shelare, K.R. Aglawe, P.N. Belkhode, Mater. Today: Proc. 54 (2022) 560–565. [15] N. Mashoofi, S. Pourahmad, S. Pesteei, Case Stud. Therm. Eng. 10 (2017) 161–168. [16] K. Hata, M. Shibahara, Int. J. Heat Mass Tran. 204 (2023) 123849. [17] D.K. Vishwakarma, S. Bhattacharyya, M.K. Soni, V. Goel, J.P. Meyer, Int. J. Therm. Sci. 196 (2024) 108677. [18] A.R. Al-darraji, S.A. Marzouk, A. Aljabr, F.A. Almehmadi, S. Alqaed, A. Kaood, Appl. Therm. Eng. 236 (2024) 121493. [19] A. Zarei, S. Seddighi, S. Elahi, R. Örlü, Appl. Therm. Eng. 200 (2022) 117559. [20] S.L. Ghashim, A.M. Flayh, J. King Saud Univ.-Eng. Sci. 33 (2021) 517–524. [21] N.M. Maleki, S. Pourahmad, Int. Commun. Heat Mass Tran. 141 (2023) 106566. [22] C. Pan, A.M. Alqahtani, H. Wei, N. Sulaiman, A.M.A. Elsiddieg, S.P. Ghoushchi, Int. J. Therm. Sci. 195 (2024) 108642. [23] T. Thungthong, N. Chalearmwattananon, T. Mongkolkitngam, W. Chaiworapuek, Int. J. Heat Mass Tran. 163 (2020) 120422. [24] B. Chen, Z. Wan, G. Chen, G. Zhong, Y. Tang, Int. Commun. Heat Mass Tran. 104 (2019) 60–69. [25] E. Shojaeizadeh, F. Veysi, K. Zareinia, A.M. Mansouri, Appl. Therm. Eng. 201 (2022) 117726. [26] B. Sun, Y. Guo, D. Yang, H. Li, Appl. Therm. Eng. 171 (2020) 114920. [27] S. Mei, C. Qi, M. Liu, F. Fan, L. Liang, Int. J. Heat Mass Tran. 134 (2019) 707–721.

Copyright

Copyright © 2025 Sharad Kumar Daheriya, Dr. Ravindra Randa. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.