The present study is concerned with forced convection heat transfer in laminar and turbulent flow with nanofluids. Nanofluids are defined as a colloidal suspension of particles in a base fluid, where the particles have a characteristic length of less than 100 nm.
Experiments were conducted to determine the qualification of nanofluids for laminar and turbulent flow forced convection heat transfer. The experiments were conducted in two different devices: Firstly, a stainless steel pipe with an inner diameter of 3.7 mm, heated directly by a DC current in the pipe wall, and secondly, a tubular heat exchanger, which the fluid was cooled down in.
The tested nanofluids were not only assessed considering Nu/Re, as it has been found to be common in a short literature review, but also by taking into account the pressure drop indifferent ways. A way of considering pressure drop in non-dimensional quantities was introduced that had not been seen in literature.
Convective Heat Transfer with Nanofluids
In some cases, an opposite assessment for the fluid could be found from comparing Nu/Re of base fluid and nanofluid and comparing h/Δp. Difficulties during validation of the test rig had called for system improvement; an extensive error investigation was conducted on the test rig and the calculation. The error investigation resulted in changes concerning the calculation and the test rig.
Source: KTH
Author: Ströder, Simon
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