International Nanofluid Properties Benchmark Exercise (INPBE)

Overview	Nanofluids	Participants	Workshop Presentations	Contact
Results: Batch 1 | Batch 2 | Batch 3 | Batch 4

Overview

Background and Objectives

Engineered suspensions of nanoparticles in liquids, known as ‘nanofluids’, have generated considerable interest for their potential to enhance the heat transfer rate in engineering systems, while reducing and possibly eliminating the issues of erosion, sedimentation and clogging that plagued earlier solid-liquid mixtures with larger particles.  While robust progress has been made towards the practical use of nanofluids, uncertainties remain concerning the fundamental effects of nanoparticles on key thermo-physical properties.  In particular, the possibility of very large thermal conductivity enhancement in nanofluids and the associated physical mechanisms are a hotly debated topic, in part because the thermal conductivity database is sparse and inconsistent.  An important source of inconsistency could lie in the broad range of experimental approaches that have been implemented to measure nanofluid thermal conductivity, e.g., transient hot wire, steady-state heated plates, oscillating temperature, thermal lensing, etc.  At the first scientific conference entirely dedicated to nanofluids (Nanofluids: Fundamentals and Applications, September 16-20, 2007, Copper Mountain, Colorado), it was decided to launch an international nanofluid property benchmark exercise (INPBE), to eliminate such inconsistency and help advance the debate on nanofluid properties.

Therefore the objectives of the exercise are:

• To validate nanofluid property measurements (particularly of thermal conductivity) performed with various experimental methods.
• To generate a reliable database of nanofluid properties (particularly thermal conductivity).

Thirty organizations from the US, UK, France, Switzerland, South Korea, India, China and Singapore participate in the exercise (participant list). INPBE will culminate in a workshop where the results of the exercise will be presented and discussed.  INPBE is conducted under the auspices and support of the National Science Foundation.

INPBE Methodology

A set of test nanofluids will be identified based on their colloidal stability and potential for enhanced thermal conductivity.  All participating organizations will be given identical samples (from a single batch), will adhere to the same sample handling protocol and will report the data within a relatively short time frame (e.g., one month) of sample delivery.  This approach aims at minimizing spurious effects due to nanofluid preparation, handling and long-term instability.  The minimum requirement to participate in the exercise is to measure and report the thermal conductivity of at least one test nanofluid at room temperature (25°C).  This measurement will have to be repeated after one day, to ensure repeatability in view of possible sedimentation.  Participants can also measure (at their discretion) thermal conductivity at higher temperature (50°C) and/or various other nanofluid properties, including (but not necessarily limited to) viscosity, density, specific heat, particle size and concentration.  The data will be reported to and organized by the exercise administrators (MIT and IIT).  A workshop will be held to present and discuss the results of the exercise.  A final publication (e.g., journal article) is envisioned to disseminate the results of the exercise.