Experimental study of the thermal behavior of spark generated bubbles in water

Experimental Determination of Temperatures in Spark Generated Bubbles Oscillating in Water

“…assumption is justified, e.g., by the results published in [12]), an equation enabling the determination of the plasma surface temperature Θ(t) has been derived in [19]. The derivation is based on the StefanBoltzman Law, the equation of energy partition during the electric discharge, the time variation of the bubble radius R(t), and the voltage u(t) at the output of the optical detector.…”

“…In the frames taken in the growth and first contraction phases, the glowing plasma core in the bubble interior can be seen. The small bright objects floating in the vicinity of the bubble are plasma packets [19].…”

“…The record of the optical radiation (represented by voltage u(t) at the output of the optical detector) consists of a pulse u 0 (t) that is radiated during the electric discharge and the subsequent explosive bubble growth, and the pulse u 1 (t) that is radiated during the first bubble contraction and the subsequent bubble expansion [19]. The dynamic range of the optical detector (the photodiode, amplifier, A/D converter) was not sufficiently high to record both u 0 (t) and u 1 (t) in a single experiment with good fidelity.…”

“…The angle brackets denote the average values on the first set of experiments. For a given bubble size R M 1 , these average values can be computed using the regression lines and the polynomial derived in [19]:…”

“…Although the reproducibility of lasergenerated bubbles may be better, it remains relatively low. This paper will show that useful estimates of the instantaneous surface temperature of the plasma core in the bubble interior can be determined using the experimental method described in [19]. In this way, autonomous behaviour of the plasma can also be proved.…”