The Sept. 12 Tech Talk article "Not so super-cool after all" did not accurately convey the conclusions reached by the lead researchers, Jacopo Buongiorno, assistant professor of nuclear science and engineering, and Lin-Wen Hu, associate director of the Nuclear Reactor Laboratory.
The article, which was approved by one member of the research team, discussed a recent paper published in Physics Review Letter (PRL), "Mean-Field Versus Micro-Convection Effects in Nanofluid Thermal Conduction."
Buongiorno and Hu submitted the following statement to Tech Talk: "As co-authors of the PRL paper and principal investigators of the nanofluid research program at MIT, we would like to clarify that we were not consulted during the preparation of this article and disagree with its conclusion. The objective of our PRL paper was to test the validity of a physical mechanism (micro-convection) that has been proposed as an explanation for thermal conductivity enhancement. Our objective was not to deduce a general conclusion about nanofluids; in fact experimental data from other laboratories [that] exist in the literature have shown abnormal enhancement, which require further study. Therefore, the statement 'the early promise of nanofluids as an advanced nanoengineered coolant remains largely unfulfilled' is unwarranted and inconsistent with the PRL paper contents. Finally, regardless of the controversy about thermal conductivity, the experiments on boiling of nanofluids at MIT are yielding positive results. The addition of small amounts of nanoparticles has significantly increased the critical heat flux, a limiting measure of heat a material can withstand with a boiling coolant. Many systems based on boiling (for example, nuclear reactors, coal-fired boilers, heat exchangers) could greatly benefit from such critical heat flux increase. This aspect was omitted from the article, further contributing to its negative tone."
A version of this article appeared in MIT Tech Talk on September 19, 2007 (download PDF).