Thermal simulation

POWDERS,HANDLING - DISPERSION OF POWDERS IN LIQUIDS] (Vol 19) Thermally simulated conductivity... 

The study shows that in this particular case a natural ventilation system is a suitable and ecological possibility to remove the high internal thermal loads. Accurate information on the internal loads and the ventilation openings is crucial for the results of the thermal simulation. 

The authors developed a multi-layered microreactor system with a methanol reforma- to supply hydrogen for a small proton exchange membrane fiiel cell (PEMFC) to be used as a power source for portable electronic devices [6]. The microreactor consists of four units (a methanol reformer with catalytic combustor, a carbon monoxide remover, and two vaporizers), and was designed using thermal simulations to establish the rppropriate temperature distribution for each reaction, as shown in Fig. 3. 

Many of the hotplate devices presented so far rely on corresponding thermal simulations that are based on model assumptions and hnite element methods (FEM) [47, 92-97]. Analytical models also have been developed [7,9,98,99] another publication describes RC-network analysis and dimension reduction [100]. A reduction of the complexity and order of the model has been successfully realized, and the dilFerent relevant approaches have been summarized in recent articles [101,102]... 

In the previous paragraph, the basic considerations of FEM modelling have been laid out. The outcome of a static thermal simulation based on this model is a 3-d temperature field T x,y,z). In this section it is discussed, how the characteristic figures, such as thermal resistance and thermal time constant of the membrane, can be deduced. 

M. Dumitrescu, C. Cobianu, D. Lungu, D. Dascalu, A. Pascu, S. Kolev, and A. van den Berg. Thermal simulation of surface micromachinedpolysUicon hotplates oflowpower consumption . Sensors and Actuators A76 (1999), 51-56. 

T. Bechthold, E.B. Rudnyi, and J.G. Korvink. Dynamic electro-thermal simulation of microsystems - a review . Journal of Micromechanics and Microengineering 15 (2005), R17-R31. 

These results are highly encouraging as they demonstrate the high power capability of the SiC RF-BJT devices along with acceptable power gain and efficiency. From thermal simulations, it is estimated that the junction temperature may reach a peak value of 171 C for pulse widths of 250 jus and 6% duty cycle without any external cooling. Since SiC junctions can easily sustain a temperature of 250 C, there is room to increase the pulse width even further. 

El-Husseini MH, Venet P, Rojat G, Joubert C. Thermal simulation for geometric optimization of metallized polypropylene film capacitors. IEEE Transactions on Industry Applications 2003 38(3) 713—718. 

Wilkerson P, Raman A, Turowski M. Fast, automated thermal simulation of three-dimensional integrated circuits. In Proceedings of Inter Society Conference on Thermal Phenomena 2004. p 706-713. 

The thermal simulation was verified by choosing a benzene concentration of zero (no reaction) and natural convection cooling only. An ambient temperature of 20°C was assumed and, to minimise calcur-lation time, the accumulation terms in the separation regions were neglected. For a 1.2 kW power input, the model predicted a steady-state catalyst temperature of 473°C which was reached about seven hours after heating was begun. A temperature loss of 42 0 between the pebble benzene mixer and the catalyst was predicted while the difference between the catalyst and the fluidized bed preheater was 57 C. This loss was attributed to the increased... 

The results of the thermal simulation were sufficiently encouraging for us to proceed to the reactor simulation for a number of steady-state operating conditions, but neglecting the maleic anhydride degradation in the fluidized bed. Both the simplified kinetic expression (equation (4)) and the more exact equation (3) were used and the results are shown in Table I as Case 1 and Case 2 respectively. 

For the two vertically stacked dies, significant thermal gradients may exist due to non-uniform on-chip power distributions. To capture such non-uniform on-chip profiles, detailed thermal modeling and analysis is employed to achieve good accuracy. For this purpose, we adopt an efficient full-chip thermal simulator 231 that is based on detailed finite difference discretization of the following governing heat transfer partial differential equation... 

To consider the temperature dependent leakage power consumption, it is desired to determine the transistor layer temperature distribution due to the power dissipated. For this purpose, the two transistor layers are laterally partitioned into M = 2 x N x N bins based on a user-specified granularity. Then, full-chip thermal simulation is applied to compute the average temperature increase in all bins if a unit power is dissipated in any of these bins. The power and temperature interactions for a particular power dissipating bin are illustrated in Fig. 5.6. A total of M x M interactions will be extracted at this stage such that for any given on-chip power dissipation distribution, the temperature increase at any of the two transistor layers can be determined by superposition at the specified granularity 23. Stated mathematically, we have... 

Figure 5.7 Thermal simulation of a set of floorplans with varying total area and...

T. Wang, C. Chen. 3-D thermal-ADI a linear-time chip level transient thermal simulator. IEEE Trans, on Computer-Aided Des. Integrated Circuits System, 2002, Vol. 21, No. 12, pp. 1434- 1445. 

Case study thermal simulation of a toroid reflecting mirror... 

To ensure the proper thermal simulation of the space environment, the absorptance of a space chamber s cold wall for both solar and room temperature radiation must be known. The absorptance of the cold-wall surface depends on the substrate coating, the type and thickness of the condensable gas deposited, and the source of incident radiation. 

Set-up for the one-dimensional model for the thermal simulation of a direct thermoelectric gas sensor. Reprinted from Rettig and Moos (2009) with permission from lOP-Publishing Ltd. 

Thermal simulation of the building flow and illumination simulations... 

The most simple methods for preparation of hafnium carbide and its composites are the follows. The powder of HfO was thermally treated with Mg in molar ratio 5 4 under a CH flow ranging from 800 to 950 °C [4]. The effective high temperature coating for carbon fiber reinforced carbon and carbon fibre reinforced silicon carbide was prepared with use of HfC [5]. For this purpose hafnium carbide layers were obtained in a thermally simulated chemical vapor deposition (CVD) reactor on nonporous substrates by reaction of hafnium tetrachloride, methane and addition of hydrogen (Eq. 10.1) ... 

The thermal model of the PM motor is built in Amesim software to analyze the temperature variation of the each part of motor. The simulation is carried out under the same condition of the test platform. The thermal simulation model of PM motor is verified by the test results. A coohng network system composed of the thermal model of PM motor is co-simulated in Amesim and Matlab. In the future research, the motor thermal performance will be investigated with the running conditions of the vehicle. 

SMP-Nitinol hybrid wire is programmed to a straightened state, in which the glassy regime of the polymer inhibits superelastic recovery of the NiTi. Upon electro-resistive heating of a thin copper wire wound around the NiTi, the SMP softens and activates, allowing both the polymer and NiTi to recover [49], The device was tested with rabbit blood clots in an in vitro setup, and thermal simulations were performed to calculate the maximum heating of the device. This device was tested in a rabbit acute arterial occlusion model in which four out of five treated clots led to complete or partial restoration of blood flow [50]. 

Evaluation of thermal histories for a 15 mm thick AS4/8552 part on a 15 mm thick Invar tool using a ID thermal simulation in COMPRO. (Re-created from reference 30.)... 

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