Studies on diesel engine exhaust gas for retrieving the waste heat through Triple Tube Heat Exchanger (TTHE) through different tubes

ABSTRACT

This paper presents a methodology to recover the waste heat from the diesel engine exhaust gas via triple tube heat exchanger (TTHE) with various intermediate tubes like corrugated tube, helically finned tube, dimpled tube, protrusion tube, and then compared with double tube heat exchanger numerically and experimentally. Due to its practical catastrophic nature by application, only limited work has been done in TTHEs. In many studies, the dimpled tube is used for only fluid flows and not used for gaseous states due to boundary layer problems. In TTHE, the intermediate tube carries exhaust gases of diesel engine, while the inside and outside of the tube carries water, respectively, where the Reynolds number (Re) varyies from 4,000 to 11,000. The rate of heat transfer and fluid flow attributes of TTHE for counter flow and parallel flow orders with different mass flow rates are investigated. The temperature variations of plain tube and different intermediate tubes are analyzed with computational fluid dynamics (CFD) and also experimentally. The outer pipe’s outer diameter is 101 mm, intermediate pipe’s outer diameter is 76 mm, and inner pipe’s outer diameter is 50 mm and the thickness of each of the three tubes is 1.5 mm with length of 2,000 mm singly. The TTHE thermal performances and fluid flow characteristics are expressed by the Nusselt number (Nu), Effectiveness (e), and overall heat transfer coefficient (U). The results obtained numerically by CFD and the experimental value of TTHE were compared with the double tube heat exchanger. The counter flow kind of TTHE with dimpled tube geometry produces the best results. The greatest waste heat recovered using dimpled tube TTHE is roughly 6.279 kW at full load circumstances, according to the findings.

KEYWORDS:

• Triple tube heat exchanger (TTHE)
• double pipe heat exchanger (DPHE)
• diesel engine
• CFD
• exhaust gas
• waste heat recovery

Disclosure statement

No potential conflict of interest was reported by the author(s).

Nomenclature

A heat transfer area (m²)

h heat transfer coefficient (W/m²K)

ƒ friction factor

Pr Prandtl number

F Heat transfer rate (W)

Re Reynolds number

C_p Specific heat capacity (kJ/kg K)

v Velocity (m/sec)

Nu Nusselt number

T Temperature (°C)

k Thermal conductivity (W/m K)

Lmtd Log Mean Temperature Difference

U Overall heat transfer coefficient (W/m²k)

Є Effectiveness

NTU Number of Transfer Units

TTHE Triple Tube Heat Exchanger

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15567036.2022.2075057.

Additional information

Notes on contributors

Mohan Raman

Mohan Raman received the B.E. degree in mechanical engineering from the Madras University, Chennai, in 2001 and M.E degree in Thermal engineering from Anna University, Chennai, in 2005 and a Ph.D. degree in Heat transfer and CPU cooling from Anna University Chennai in 2012. He currently works as Professor in Mechanical engineering department in Sona College of Technology, Salem. His current research interests include the Heat transfer, Thermal engineering and CPU Cooling. He has published over 50 papers in peer reviewed journals and international conferences.

Perumal Saravanan

Perumal Saravanan received the B.E. degree in mechanical engineering from the Anna University, Thiruchirapalli, in 2012 and M.E degree in CAD from Anna University, Chennai in 2014 and currently doing a Ph.D. degree in Heat transfer in Anna University Chennai. He currently works as Assistant professor in Mechanical engineering department in Muthayammal engineering college, Namakkal. His current research interests include the Heat transfer, Thermal engineering and Nanofluids. He has published over 25 papers in peer reviewed journals and international conferences.

Suresh Muthusamy

Suresh Muthusamy received the bachelor’s degree in Electrical and Electronics Engineering and the master’s degree in Power Electronics and Drives during the year 2009 and 2011 from Anna University, Chennai and Anna University, Coimbatore respectively. Currently, he is working towards the Ph.D. degree in Electrical Engineering at Anna University, Chennai in the area of Hybrid Renewable Energy Systems. Since 2011, he has been working as Assistant Professor Senior Grade in the Department of Electronics and Communication Engineering at Kongu Engineering College (Autonomous), Perundurai, Erode. He published more than 75 research articles in the reputed international journal publications like Elsevier, Springer, Taylor & Francis, SAGE, ASME, etc & indexed in SCI, SCIE, Scopus and Web of Science with good impact factor and also presented many papers in national and international conferences. His areas of interests include hybrid renewable energy systems, power electronic converters, hybrid electric vehicles and battery management systems.

Shankar Subramaniam

Shankar Subramaniam received the bachelor’s degree in Mechanical Engineering, master’s degree in Engineering Design from Bharathiyar University, Coimbatore and the Ph.D degree in the area of Machine Design/Contact Mechanics from Indian Institute of Technology, Madras during the year 2001, 2002 and 2008 respectively. He is currently working as Professor in the Department of Mechatronics Engineering at Kongu Engineering College (Autonomous), Perundurai, Erode. He published more than 120 research articles in reputed journals. His research interest includes computational mechanics, tribology, biomechanics, ergonomics, finite element analysis, etc.