Pulsating Heat Pipe (PHP) has received significant attention in the field of electronics cooling due to its simplicity, manufacturing ease and versatility. PHP involves intricate internal gas-liquid two-phase therm-hydrodynamics. The present paper is an effort to understand this complex hydrodynamics under adiabatic and diabatic conditions. Experimental investigations are reported for air-water two-phase flow through 2.12 mm horizontal circular minichannel. The influence of individual gas and liquid inlet flow rates on Taylor bubble velocity, void fraction, liquid holdup and lengths of the liquid slug and Taylor bubble, frictional pressure drop and heat transfer in continuous Taylor bubble train flow (CTB) is analysed. The findings of the present investigation could be helpful to develop mathematical model for PHP for future research. (C) 2015 Elsevier Ltd. All rights reserved.