An investigation of pool boiling under alternating magnetic field and steady-state conditions

Document Type : Research Article

Authors

1 Department of Mechanical Engineering, Yazd University, Yazd, Iran

2 Department of Mechanical Engineering, Yazd University

3 Faculty of Aerospace Engineering, Shahid Sattari Aeronautical University of Science and Technology, Tehran, Iran

Abstract

Applying an alternating magnetic field around the pool boiling region has various effects on the pool boiling's major characteristics. Steady-state pool boiling experiments were performed with deionized water under atmospheric pressure and the application of an alternating magnetic field. A nickel-chrome wire with a diameter of 0.1 mm was used as a heater. The magnetic field was generated by applying a pair of Helmholtz coils. The effects of applying this field with intensities of 5.8, 8.9, and 13.3 mT on pool boiling parameters were investigated in experiments and compared to the state without a magnetic field. The results show that, in general, the application of a magnetic field shortens the pool boiling process and delays the start of the nucleate boiling regime (ONB ). The critical heat flux (CHF) did not vary significantly when alternating magnetic fields were used. In comparison to no magnetic field application, this parameter decreased by 1.38%, 2.31%, and 3.33% at magnetic field intensities of 5.8, 8.9, and 13.3 mT. But the boiling heat transfer coefficient (BHTC) has increased to a maximum of 47% at the CHF point. The Lorentz force acting on water molecules reduced the number of bubbles surrounding the wire heater, allowing the heat produced to be transferred to the surrounding liquid more quickly. As a result, the BHTC increased with increasing magnetic field strength.

Keywords

Main Subjects