Proceedings of Symposium on Energy Engineering in the 21st Century (SEE2000) Volume I-IV

ISBN Print: 1-56700-132-7

MICROSCALE HEAT TRANSFER AT FAST TIME STUDIED BY NOVEL LASER-BASED MEASUREMENT TECHIQUES

DOI: 10.1615/SEE2000.810
pages 680-686

Abstract

In present paper we report on the first study of transient microscale heat transfer in liquid which contained the nature organic material of Chinese tea solution. Heat transport by phonons has been studied by single picosecond pulse degenerate four wave mixing (DFWM) technique. The sound velocity in Chinese tea solution was measured as 1133.6 m/s which is compared with the sound velocity in methanol. The molecules of Chinese tea can absorb a photon and then relax non-radiatively or radiatively back to the electronics ground state. Ultrafast laser induced fluorescence (ULIF) at 674. lnm was recorded and radiative transition for the Chinese tea molecules was very strong. Convection in Chinese tea solution has also been studied by self action with both horizontal- and vertical laser propagation through the Chinese tea cell. The dependence of the location of the red ULIF on the intensity of the laser beams clearly show that the real behavior of Chinese tea molecules in transient heat transport.