Cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during laser dermatologic therapy. However, the dominant mechanisms of heat transfer during the transient cooling process are incompletely understood. The objective of this study is to elucidate the physics of CSC by measuring the effect of initial substrate temperature (T0) on cooling dynamics. Cryogen was delivered b...

A technique for determining the heat transfer on the far surface of a wall based on measuring the heat transfer and temperature on the near wall is presented. Although heat transfer measurements have previously been used to augment temperature measurements in inverse heat conduction methods, the sensors used alter the heat flow through the surface, disturbing the very quantity that is desired t...

Heat transfer during compression of air in a long, thin tube is studied by CFD. The tube represents one of the many in a honeycomb geometry inserted in a liquid piston air compressor to minimize temperature rise. A dimensionless number for the heat flow rate that includes the changing heat transfer area between the tube wall and air during compression is used. From the CFD results, alinear rela...

The inverse analysis is encountered in various branches of science and engineering. In the field of heat transfer, inverse analysis is used for the estimation of surface conditions such as temperature and heat flux. Also, the determination of thermal properties such as thermal conductivity and heat capacity of solids by utilizing transient temperature measurements collected from points within t...

using of nanofluids and ducts with corrugated walls are both supposed to enhance heat transfer, by increasing the heat transfer fluid conductivity and the heat transfer area respectively. use of a diverging duct with a jet at inlet section may further increase heat transfer by creating recirculation zones inside the duct. in this work two-dimensional incompressible laminar flow of a nanofluid e...

sometimes the need for non-circular ducts arises in many heat transfer applications because of lower pressure drop of non-circular cross section such as square duct compared to circular tube, particularly in compact heat. but square cross section has poor heat transfer performance and it is expected that using a nanofluid as a new heat transfer media may improve the heat transfer performance of...

abstract: in this study, al 2 o 3 /eg and tio 2 /eg nanofluids as coolants have been used in the double-tube heat exchanger. the hot solvent inlet heat exchanger must be cooled down with a specified amount. we can use nanofluids as coolants in the heat exchanger for optimization of the heat transfer area. therefore, the efficacy of nanofluids as coolants is verified. furthermore, flow rate of c...

It is shown that there exists an optimal spacing of thermo-sensors in the determination of the experimental heat transfer coefficient of a fluid flowing over a plate. The problem is considered as an inverse heat transfer problem with long thin fin model. The heat transfer coefficient of the fluid is estimated from simulated steady-state temperature measurements along the plate. It is shown theo...