in this study, thermal performance of a cylindrical heat pipe is investigated numerically. three different types of water based nanofluids, namely (al2o3+water), (diamond+water) and (multi-wall carbon nano tube (mwcnt) +water) have been used. the influence of using the simple nanofluids and mwcnt nanofluid on the heat pipe characteristics such as liquid velocity, pressure profile, temperature p...

The principle of heat transfer enhancement in the core flow of a tube has been proposed, in this paper, to make fluid temperature uniform in the core region of a tube and decrease flow resistance, which is different from heat transfer enhancement in the boundary flow of a tube. Two new models, representing heat transfer enhancement in the laminar and turbulent tube flow, have been established a...

The crystallinity and acoustic-vibration parameters of Picea jezoensis, including specific Young’s modulus (E/ρ),coefficient of sound-radiation resistance (R), sound resistance (ω), and the ratio of Young’s modulus to the dynamic stiffness modulus (E/G), before and after heat treatment were measured and characterized. Conditions for the heat treatment included N2 as the protection gas and tempe...

An electric current from a ferromagnet into a nonmagnetic material can induce a spin-dependent electron temperature. Here, it is shown that this spin heat accumulation, when created by tunneling from a ferromagnet, produces a non-negligible voltage signal that is comparable to that due to the coexisting electrical spin accumulation and can give a different Hanle spin precession signature. The e...

This paper presents a study of the thermal spreading resistance Rth of a small heat source on a conductive substrate subject to bottomside convective cooling. This problem has been investigated for a very long time and is well covered in the literature. However, instead of using the design curves found in many papers, the results are presented as function of the heat transfer coefficient h. Doi...

Abstract: During solidification and casting in metallic molds, the heat flow is controlled by the thermal resistance at the casting-mold interface. Thus heat transfer coefficient at the metal- mold interface has a predominant effect on the rate of heat transfer. In some processes such as low pressure and die-casting, the effect of pressure on molten metal will affect the rate of heat transfer a...

Heat at the junction of light-emitting diodes (LED) affects the overall performance of the LED in terms of light output, spectrum, and life. Usually it is difficult to measure junction temperature of a LED directly. There are several techniques for estimating LED junction temperature. One-dimensional heat transfer analysis is one of the most popular methods for estimating the junction temperatu...

Pulsating heat pipe is an efficient heat exchange device which is being used for cooling and heating recovery. In the present work, we made a closed-loop pulsating heat pipe with six U-turns and we used water in our system. Moreover the use of water-Fe3O4 nanofluid was studied with two different filling ratios 40% and 50% and 1% mass concentration. At the end we calculated heat resistance and h...

Pulsating heat pipe is an efficient heat exchange device which is being used for cooling and heating recovery. In the present work, we made a closed-loop pulsating heat pipe with six U-turns and we used water in our system. Moreover the use of water-Fe3O4 nanofluid was studied with two different filling ratios 40% and 50% and 1% mass concentration. At the end we calculated heat resistance and h...

In internal combustion engines, exhaust valve and its seat gain considerable temperature as the hot gases exit through them. So, the rate of heat transfer should be under control. In this study, the contact heat transfer coefficient has been estimated. An experimental study on an Air-Cooled internal combustion engine cylinder head has been considered. Using the measured temperatures of sensors ...