Heat transfer enhancement with gas-to-gas micro heat exchangers

Using Burnett Equations to Derive an Analytical Solution to Pressure-Driven Gas Flow and Heat Transfer in Micro-Couette Flow

The aim of the present study is deriving an analytical solution to incompressible thermal flow in a micro-Couette geometry in the presence of a pressure gradient using Burnett equations with first- and second-order slip boundary conditions. The lower plate of the micro-Couette structure is stationary, whereas the upper plate moves at a constant velocity. Non-dimensional axial velocity and tempe...

Heat Transfer to Separation Flow in Heat Exchangers

Development and Testing of Microscale Silicon Heat Exchangers for the MIT Micro Gas-Turbine Engine

Micro-scale silicon heat exchangers were designed, modeled using conventional heat transfer and fluid mechanics correlations, fabricated in the MIT Microtechnologies Laboratory, and tested as part of the MIT micro-gas turbine engine project. Heat transfer and pressure drop experiments were carried out to measure the performance of these heat exchangers, and to validate the predictions of the mo...

Heat Transfer on a Hypersonic Sphere with Gas Injection

The interaction of a diffusing outgas flow from a sphere nose opposing a hypersonic free stream is studied numerically using the direct simulation Monte-Carlo technique under the transitional rarefied-gas-flow regime conditions at Knudsen numbers from 0.016 to 1.5 and blowing factors from 0.15 to 1.5. Strong influences of the blowing factor (the ratio of outgas mass flux to upstream mass flux) ...

Nanofluids for Heat Transfer Enhancement – A Review

A nanofluid is a dilute liquid suspension of particles with at least one critical dimension smaller than ~100 nm. Research works so far suggest that nanofluids offer excellent heat transfer enhancement over conventional base fluids. The enhancement depends on several factors such as particle shape, particle size distribution, volume fraction of nanoparticles, temperature, pH, and thermal conduc...