Experimental implementation of thermal enhancement performance of air heat exchanger’s pipes utilizing unconventional turbulator

Keywords: air heat exchanger, thermal performance, heat transfer, hexagonal turbulators, heat losses


Heat exchangers are widely used in industry, however, raising their performance are important for the variety of applications. Consequently, efficiency improvement associated with low production cost is considered in this experimental work. The current study aims to enhance the rate of heat transfer in pipe-type heat exchangers experimentally by using a novel nozzle as a turbulator. The cross-sectional shape of the nozzle is hexagonal, and the diameter ratio DR is equal to 0.5. Constant heat flux was maintained in the vicinity of the section of the test tube, while the working fluid was pumped into the open system at six discrete Reynolds number values ranging from 6000 to 19500. To investigate the effect of distance among the pieces, three turbulators with different numbers were assigned and named as (N=4, 5 and 6). The results indicated an increase of 172 %, 194 % and 216 % of the heat transfer rate for cases 4, 5 and 6 respectively comparing to the benchmark tube. On the other hand, the friction factor values increased remarkably due to the inserting of turbulators by about of 722.9 % for N=4, 823.9 % for N=5 and 886.7 % for N=6 compared to a plain tube case. Moreover, it has been established that with the insertion of 6 pieces two enhancements was observed; heat transfer rate and thermal performance, where, thermal performance of all cases exceeds unity (maximum thermal performance of 1.62 has been obtained by inserting 6 pieces of hexagonal nozzles turbulators). A comparison with another types of vortex generators shows the gap between the turbulator and heated surface offers a solution for problems occurred in the pipes of heat exchanger. The study therefore suggests a wider practical implementation of the turbulators


Download data is not yet available.

Author Biographies

Ali Abdulwahab Ismaeel, University of Technology - Iraq

Department of Electromechanical Engineering

Nassr Fadhil Hussein, University of Technology - Iraq

Department of Electromechanical Engineering

Kadhim H. Suffer, Al-Nahrain University

Department of Mechanical Engineering

Zuradzman M Razlan, Universiti Malaysia Perlis

Faculty of Mechanical Engineering Technology


Promvonge, P., Eiamsa-ard, S. (2007). Heat transfer behaviors in a tube with combined conical-ring and twisted-tape insert. International Communications in Heat and Mass Transfer, 34 (7), 849–859. doi: https://doi.org/10.1016/j.icheatmasstransfer.2007.03.019

Promvonge, P., Eiamsa-ard, S. (2007). Heat transfer in a circular tube fitted with free-spacing snail entry and conical-nozzle turbulators. International Communications in Heat and Mass Transfer, 34 (7), 838–848. doi: https://doi.org/10.1016/j.icheatmasstransfer.2007.03.020

Promvonge, P., Eiamsa-ard, S. (2007). Heat transfer augmentation in a circular tube using V-nozzle turbulator inserts and snail entry. Experimental Thermal and Fluid Science, 32 (1), 332–340. doi: https://doi.org/10.1016/j.expthermflusci.2007.04.010

Kongkaitpaiboon, V., Nanan, K., Eiamsa-ard, S. (2010). Experimental investigation of heat transfer and turbulent flow friction in a tube fitted with perforated conical-rings. International Communications in Heat and Mass Transfer, 37 (5), 560–567. doi: https://doi.org/10.1016/j.icheatmasstransfer.2009.12.015

Mohammed, A. A., Mohammed, B. A., Muhee, R. J. (2014). Heat Transfer Enhancement in a Tube Fitted with NozzleTurbulators, Perforated Nozzle-Turbulators with Different hole shap. Eng. &Tech.Journal, 32 (10), 2514–2527. Available at: https://www.iasj.net/iasj/download/e2fb7c5de16daa32

Promvonge, P. (2008). Heat transfer behaviors in round tube with conical ring inserts. Energy Conversion and Management, 49 (1), 8–15. doi: https://doi.org/10.1016/j.enconman.2007.06.009

Muthusamy, C., Vivar, M., Skryabin, I., Srithar, K. (2013). Effect of conical cut-out turbulators with internal fins in a circular tube on heat transfer and friction factor. International Communications in Heat and Mass Transfer, 44, 64–68. doi: https://doi.org/10.1016/j.icheatmasstransfer.2013.03.004

Gowrisankar, K., Kishore, P. S. (2015). Augmentation Heat Transfer in a Circular Pipe using Divergent Nozzle as Insert. International Journal for Research in Applied Science & Engineering Technology (IJRASET), 3 (IX), 143–149. Available at: https://www.researchgate.net/publication/338595178_Augmentation_Heat_Transfer_in_a_Circular_Pipe_using_Divergent_Nozzle_as_Insert

Mohammed, A. A. (2011). Heat Transfer and Pressure Drop Characteristics of Turbulent Flow in a Tube Fitted with Conical Ring and Twisted Tape Inserts. Eng. & Tech. Journal, 29 (2), 226–239. Available at: https://www.iasj.net/iasj/download/58ddc235d70daea0

Tirupati Rao, V., Rupesh Venkata Ramana, A., Dharma Raju, T. (2017). Augmentation heat transfer in a circular tube using conical ring and twisted tape insert. International Journal of Scientific Research Engineering & Technology (IJSRET), 6 (1), 45–52. Available at: https://www.researchgate.net/publication/342436781_AUGMENTATION_HEAT_TRANSFER_IN_A_CIRCULAR_TUBE_USING_CONICAL_RING_AND_TWISTED_TAPE_INSERT

Hasan, I. (2014). Thermal Characterization of Turbulent Flow in A Tube with Discrete Coiled Wire Insert. Journal of Engineering and Development, 18 (6), 126–143. Available at: http://www.jeasd.org/images/2014edition/issue_6/9.Thermal.Characterization.of.Turbulent.Flow.in.a.Tube.With.Discrete.Coiled.Wire.Insert.pdf

Man, C., Lv, X., Hu, J., Sun, P., Tang, Y. (2017). Experimental study on effect of heat transfer enhancement for single-phase forced convective flow with twisted tape inserts. International Journal of Heat and Mass Transfer, 106, 877–883. doi: https://doi.org/10.1016/j.ijheatmasstransfer.2016.10.026

Suri, A. R. S., Kumar, A., Maithani, R. (2017). Heat transfer enhancement of heat exchanger tube with multiple square perforated twisted tape inserts: Experimental investigation and correlation development. Chemical Engineering and Processing: Process Intensification, 116, 76–96. doi: https://doi.org/10.1016/j.cep.2017.02.014

Eiamsa-ard, S., Wongcharee, K., Eiamsa-ard, P., Thianpong, C. (2010). Heat transfer enhancement in a tube using delta-winglet twisted tape inserts. Applied Thermal Engineering, 30 (4), 310–318. doi: https://doi.org/10.1016/j.applthermaleng.2009.09.006

Patil, A. S., Kore, S. S., Sane, N. K. (2019). Thermal performance of tube exchanger enhanced with hexagonal ring turbulators. Experimental Heat Transfer, 33 (5), 455–470. doi: https://doi.org/10.1080/08916152.2019.1656302

Tamna, S., Kaewkohkiat, Y., Skullong, S., Promvonge, P. (2016). Heat transfer enhancement in tubular heat exchanger with double V-ribbed twisted-tapes. Case Studies in Thermal Engineering, 7, 14–24. doi: https://doi.org/10.1016/j.csite.2016.01.002

Bhuiya, M. M. K., Azad, A. K., Chowdhury, M. S. U., Saha, M. (2016). Heat transfer augmentation in a circular tube with perforated double counter twisted tape inserts. International Communications in Heat and Mass Transfer, 74, 18–26. doi: https://doi.org/10.1016/j.icheatmasstransfer.2016.03.001

Sheikholeslami, M., Gorji-Bandpy, M., Ganji, D. D. (2015). Experimental study of the influence of perforated circular-ring on pressure loss and heat transfer enhancement using sensitivity analysis. Applied Thermal Engineering, 91, 739–748. doi: https://doi.org/10.1016/j.applthermaleng.2015.08.068

👁 37
⬇ 37
How to Cite
Ismaeel, A. A., Hussein, N. F., Suffer, K. H., & Razlan, Z. M. (2021). Experimental implementation of thermal enhancement performance of air heat exchanger’s pipes utilizing unconventional turbulator. EUREKA: Physics and Engineering, (3), 35-44. https://doi.org/10.21303/2461-4262.2021.001850