scholarly journals 3D-printed tubes with complex internal fins for heat transfer enhancement—CFD analysis and performance evaluation

AIMS Energy ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 27-47
Author(s):  
Chao Wei ◽  
◽  
Gabriel Alexander Vasquez Diaz ◽  
Kun Wang ◽  
Peiwen Li ◽  
...  
Author(s):  
Chao Wei ◽  
Gabriel Alexander Vasquez Diaz ◽  
Kun Wang ◽  
Peiwen Li

Abstract Additive manufacturing (AM), also known as 3D printing technology, is applied to fabricate complex fin structures for heat transfer enhancement at inner surface of tubes, which conventional manufacturing technology cannot make. This work considered rectangular fins, scale fins, and delta fins with staggered alignment at the inner wall of heat transfer tubes for heat transfer enhancement of internal flows. Designed fin structures are trial-printed using plastic material to exam the printability. Laminar flow convective heat transfer has been numerically studied, and heat transfer performance of the tubes with 3D-printed interrupted fins has been compared to that with conventional straight continued fins. The benefit from heat transfer enhancement and the loss due to increased pumping pressure is evaluated using the total entropy generation rate in the control volume of heat transfer tube. As the conclusion of the study, better heat transfer tubes with 3D-printed internal fins are recommended.


Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3041 ◽  
Author(s):  
Budi Kristiawan ◽  
Agung Tri Wijayanta ◽  
Koji Enoki ◽  
Takahiko Miyazaki ◽  
Muhammad Aziz

A combination of two passive heat transfer enhancement techniques using a microfin structure and nanofluids was investigated numerically. TiO2/water nanofluids flowing inside a square minichannel with a microfin structure (SMM) were observed as a practical application. Increased heat transfer performance was investigated by observing the Nusselt number, friction factor, and performance evaluation criterion (PEC). Velocity and temperature profiles were also demonstrated at a laminar developing flow regime. The SMM used in this work had six microfins (N = 6) and TiO2/water nanofluids with various nanoparticle concentrations of 0.005, 0.01, and 0.1 vol.%. By combining nanofluids as working fluids and SMM as a passive heat transfer enhancement, the maximum PEC value of 1.2 was achieved at Re = 380 with a volume fraction of 0.01 vol.%. It is obvious that compared to water flowing inside the square minichannel microfin, the heat transfer can be increased by using only a nanofluid with a volume fraction of 0.01%. The combination of a microfin and nanofluids as working fluids is strongly recommended due to its excellent performance in terms of heat transfer and economic considerations.


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