https://orcid.org/0000-0002-8788-7497
![Sample our Engineering & Technology journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5933/TOC-Subject-Sample-2021-Engineering-Tech.jpg"})
ABSTRACT
The current work reports an experimental study on hydrothermal improvement in a chevron plate-fin heat exchanger combined with holes and winglets. The experiments are performed for water flow through a test square duct fitted with enhanced chevron plate-fins for the Reynolds number from 4000 to 10000. Characteristics of the enhanced chevron plate-fins include three waviness aspect ratios and four different arrangements of holes and winglets at a constant diameter of holes and width/height of winglets. An overall performance factor is applied to obtain the optimal geometry. Then, only the optimal geometries are applied to find out the effect of Al2O3/water nanofluid flow on the performance of a plate-fin heat exchanger. In comparison to simple chevron plate-fins, the enhanced ones would increase the Nusselt number by a factor between 1.05% and 1.6%. In addition, simultaneous application of the optimal enhanced chevron plate-fins and the nanofluid could increase the Nusselt number. The best working conditions of this system are detected for the nanofluid at a weight fraction of 0.3%.
Nomenclature
| A | = | total surface area, m2 |
| cp | = | specific heat capacity, J kg−1 K−1 |
| Dh | = | hydraulic diameter, m |
| G | = | mass velocity, kg m−2 s−1 |
| h’ | = | heat transfer coefficient W m−2 K−1 |
| L | = | test section length, m |
| Qconv | = | convective heat transfer rate, W |
| p | = | pressure, Pa |
| ∆p | = | pressure drop, Pa |
| T | = | temperature, K |
| ∆T | = | temperature difference, K |
| V | = | volumetric flow rate, m3 s−1 |
Greek symbols
| ρ | = | density, kg m−3 |
| κ | = | thermal conductivity, W m−1 K−1 |
Dimensionless groups
| f | = | Friction factor |
| Nu | = | Nusselt number |
| Pr | = | Prandtl number |
| Re | = | Reynolds number |
Subscripts
| b | = | bulk fluid |
| Enh | = | enhanced |
| in | = | inlet |
| LMTD | = | logarithmic mean temperature difference |
| out | = | outlet |
| PP | = | pumping power |
| Sim | = | simple |
| w | = | wall |
Acronyms
| OPF | = | overall performance factor |
Acknowledgments
Supports for this work by the Islamic Azad University of Shahrood Branch are gratefully acknowledged.