AUTHOR: Md. Motiur Rahman, Dr. Debasish Sarker, Tanbin Mahmud
AFFILIATION: Department of Mechanical Engineering, International University of Business Agriculture and Technology, Dhaka, Bangladesh
DOI: https://doi.org/10.31224/6262
KEY WORDS: Forced convection, Axially grooved circular tube, Rectangular groove, Numerical heat transfer
ABSTRACT: Numerous heating and cooling procedures across several sectors make use of heat exchangers.The fluid’s flow and heat transfer characteristics inside the heat exchanger tube have an impact on the efficiency of the device. This study analyses the flow and heat transfer characteristics of water within a straight circular tube with axially grooved inner surface. For this investigation, a 3D numerical model for straight circular pipe of 11.08 mm diameter and 1920 mm length was developed with water as the heat transfer fluid and validated using published experimental data. The simulation was done for a range of Reynolds numbers (1500– 23,000) and with four axial grooving of (1 mm × 0.5 mm) on the inner surface of tube. The results revealed that the axial grooving in the inner surface of the tube significantly increases the heat transfer between 2% and 10%. The pressure drop along the tube also slightly increased between 0.1% and 1.6%. The overall efficiency increases between 5% and 12% by using inner surface grooved tube.
CAD Model
Smooth Tube
Axially Grooved Tube
Conclusion
In this investigation, characteristics of flow pattern and heat performance using a varying range of Reynolds number are analyzed numerically for smooth and grooved tube. This analysis is carried out to find the effect of overall heat transfer efficiency of the inner surface grooved tube. Based on this investigation the following conclusions can be drawn.
The numerical outcomes and experimental results are in good agreement. The higher error variance of the heat rate is about 5.59%.
The value of pressure drop for the grooved tube was higher than the smooth one for different Reynolds number, by about 0.168%- 1.68%.
The value of heat transfer rate for the grooved tube was higher than the smooth one for different Reynolds number, by about 2%- 10%.
The highest overall thermal efficiency increment is more than 12% for low Reynolds number at 1573.