Boiling--a process that has powered industries since the steam age--is governed by bubble formation. State-of-the-art boiling surfaces often increase bubble nucleation via roughness and/or wettability modification to increase performance. However, without active in situ control of bubbles, temperature or steam generation cannot be adjusted for a given heat input. Here we report the ability to t...

Measurement of cardiac output is often investigated using a technique based on hot-film anemometry. Here, we discuss a modification to hot-film anemometry, which involves a cylindrical heating element mounted flush on the surface of a typical Swan-Ganz catheter. In contrast to traditional thermodilution, the method discussed here has the potential to allow continuous monitoring of cardiac outpu...

Two-dimensional finite element modeling procedures are addressed to predict the residual stresses for multipass welds. A generalized plane strain model with a five-pass weld in a plate and an axisymmetric model with a six-pass girth weld in a pipe are considered. Element rebirth and pass-lumping techniques are employed in both models. The combined heat input using surface and body flux componen...

Type IV cracking refers to the premature failure of a welded joint due to an enhanced rate of creep void formation in the fine grained or intercritically annealed heat affected zone. A great deal of research effort has been directed at understanding the underlying mechanisms for this type of failure, but most have approached the problem from a metallurgical standpoint, and comparatively little ...

The objective of this study is to numerically investigate the temperature and heat transfer characteristics of the voice coil for a woofer with and without bobbins using the thermal equivalent heat conduction models. The temperature and heat transfer characteristics of the main components of the woofer were analyzed with input powers ranging from 5 W to 60 W. The numerical results of the voice ...

In this paper, we propose a method of improving the efficiency of thermoelectric generators (TEGs) by using a lens to concentrate heat on the heat source of a TEG. Initial experiments performed using discrete components show about 60mV increase in the amount of voltage generated when using a magnifying lens. Simulation results on the proposed TEG configuration exhibit up to 16% efficiency when ...

Abstract—The paper describes the modeling and simulation of the heat pumps domain processes. The main objective of the study is the use of the heat pump in propene–propane distillation processes. The modeling and simulation instrument is the Unisim® Design simulator. The paper is structured in three parts: An overview of the compressing gases, the modeling and simulation of the freezing systems...

In conventional wire drawing the diameter of a wire or rod-like workpiece is reduced by drawing it through a conical die. Dieless drawing of a wire or a rod is realized by a localized heating of the work piece. As heat source for example an induction coil can be used. Immediately after having passed the heating zone the work piece is cooled to restrict the heat input on very small region. By ap...

Loop heat pipe evaporators operating under steady state conditions were numerically investigated to describe evaporator characteristics and evaluate evaporator performance. Numerical solutions were obtained for conjugate flow and heat transfer in primary evaporator components. Two geometrical configurations used for cylindrical LHP evaporators, a non-bayonet evaporator and a bayonet evaporator,...

The thermal influence of carbon nanotubes (CNTs) on the PA12 in the laser sintering process was assessed by physical experiments and a three dimensional simulation model. It appears that, by adding the CNTs into the PA12 matrix, the thermal conductivity increased. A double ellipsoidal heat flux model was applied to input a three dimensional, continuous moving, volumetric laser heat source. The ...