MEASURING TRANSPORT PROPERTIES OF NANOFLUIDS M.N. Pantzali, N.A. Kazakis, N. Tsolakidis and A.A. Mouza Laboratory of Chemical Process and Plant Design Department of Chemical Engineering, Aristotle University of Thessaloniki Univ. Box 455, GR 54124 Thessaloniki, GREECE, mouza@cheng.auth.gr J. Tihon Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic ABSTRACT The study of nanofluids has lately gained scientific interest, due to their enhanced thermal con- ductivity, which would significantly improve the performance of heat transfer equipment. This work is part of a bilateral scientific program between the AUTh and the Institute of Chemical Process Fundamentals of the Czech Academy of Sciences, whose purpose is to study the rheological behaviour of nanofluids as well as their effect on the performance of commercial compact heat exchangers. The aim of the present work is to measure the thermophysical prop- erties of nanofluids consisting of nanoparticles suspended in a conventional working fluid. INTRODUCTION The design of energy-efficient heat transfer equipment, as well as the research for enhancing thermal capability of conventional fluids, contributes to the effort for better energy manage- ment. In the past, the thermal conductivity of working fluids has been augmented by suspend- ing millimetre- or micrometre-sized particles in a base fluid. However, it has not been of inter- est for practical applications due to problems such as sedimentation, erosion, clogging, fouling and increased pressure drop of the flow channel. Lately, technological progress has led to the development and production of metal particles in nanometre scale, which, when dispersed in a conventional base fluid, appreciably enhance its thermal conductivity. Water, ethylene glycol and various kinds of oils are usually employed as base fluids. It seems that these suspensions, called nanofluids, can possibly overcome the aforementioned problems, because the particles are ultra-fine and are usually used at low particle concentrations [1]. The aim of the present work is to measure the thermophysical properties (i.e. thermal conduc- tivity, viscosity and surface tension) of nanofluids consisting of multi-wall carbon nanotubes (MWCNT) or copper and aluminium oxide nanoparticles suspended in a conventional working fluid (e.g. water, ethylene glycol).The ultimate goal is to investigate the effect of the use of nanofluids on the performance of commercial heat transfer equipment. LITERATURE REVIEW The majority of the work published on nanofluids concerns mainly their thermal conductivity, whose increase depends on many factors, such as the type and dimensions of the particles and their concentration in the nanofluid. Wang & Mujumdar [2] in a comprehensive review article summarize the work done on this field. The works included in the review report different levels of thermal conductivity enhancement, e.g. 20-55% for copper nanofluids, greater than 10% for