Thermal performance of natural circulation loop filled with Al2O3/Water nanofluid

Document Type : Reasearch Paper

Authors

• Praveena Devi Nagireddy ¹
• Srinivasa Rao Chalamalasetti ²
• Kiran Kumar Kupireddi ³

¹ Mechanical Engineering Department, SR University, Warangal, Telangana-506371, India.

² Mechanical Engineering Department, Andhra University, Visakhapatnam, Andhra Pradesh, India.

³ Mechanical Engineering Department, National Institute of Technology Warangal, Telangana, India.

10.22034/ijnd.2021.681099

Abstract

Natural Circulation Loop (NCL) which is also called as a thermosyphon system is the heat transfer loop which uses no pump or external device to drive the loop fluid. In the present paper, a comparative study on thermal characteristics of two loop fluids viz. water and Al₂O₃/water nanofluid is made. Experiments are conducted on in-house designed test rig. Thermo-hydraulic behaviour of loop fluid is presented. Two parameters such as heat input, nanofluid concentration are varied in order to study their individual and combined effects. It is concluded that Al₂O₃/water nanofluid as loop fluid results in higher mass flow rates as compared to the water. Different derived quantities such as Nusselt number and Grashof number are calculated. Quantitative comparison is made between water and Al₂O₃/water nanofluid. Time to reach steady state is reduced by 22 % using Al₂O₃/water nanofluid as loop fluid when compared with water. Mass flow rate and Grashof number of the Al₂O₃/water nanofluid based NCL are enhanced by 6.75% and 26% respectively, when compared with water-based NCL at 1000W heat input. At the heater, the temperature gradient is reduced by 30.2% due to the improved thermal and transport properties of Al₂O₃/water nanofluid when compared with water at 1000 W heat input. As particle concentration increases from 1% to 5%, Nusselt number increases from 10.1 to 20.1, for the heat input of 1000W.

Keywords

• Grashof Number
• Heat Transfer Enhancement
• Nanofluid
• NCL
• Nusselt Number
• Thermal Performance

20.1001.1.20088868.2021.12.3.7.6

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