Electrohydrodynamically enhanced flow boiling in an eccentric horizontal cylindrical channel

Experimental and numerical investigations have been conducted to study the effect of electrode position in a 10.92 cm i.d. cylindrical flow channel on the electrohydrodynamically (EHD) enhanced flow boiling. The experiments were conducted for tube-side boiling of HFC-134a at dc voltage from 0 to 8 kV, liquid mass flux from 0 to 500 kg/m2s, inlet quality from 0 to 50%, and 3 vertical electrode positions within the tube (0 mm and 2.73 mm from centreline). Numerical simulation of electrical field profiles was conducted by finite element methods for various flow regimes. The results show that the heat transfer was enhanced up to 160% by EHD forces while only 20% pressure drop increase was observed. The results also show that the EHD heat transfer enhancement increases with increasing applied voltage and decreases with increasing mass flux. The effects of electrode vertical position on the EHD heat transfer enhancement will be discussed in detail based on numerical results.