Influence of Compound Heat Conductivity on the Temperature Distribution in Rotor Type Curemeters

1991 ◽  
Vol 19 (2) ◽  
pp. 68-78
Author(s):  
G. K. Ernst
Keyword(s):  
Temperature Distribution ◽  
Temperature Gradient ◽  
Temperature Dependence ◽  
Heat Conductivity ◽  
Effective Temperature ◽  
Heat Sink ◽  
Cross Linking ◽  
Temperature Calibration ◽  
Measured Rate ◽  
Rotor Type

Abstract The effective temperature in rotor type curemeters is — according to DIN 53529 — controlled using an unfilled EPDM compound with dicumylperoxide as cross-linking agent. The rate of DCP decomposition has a well-known temperature dependence. This rate is also in all practical cases the same as the rate of cross-linking. Therefore, the measured rate of cross-linking indicates the effective temperature in the reaction cavity. The rotor in common curemeters is clamped. Because it can not be heated directly, this rotor is a heat sink in the cavity. The effect is a temperature gradient in the cavity depending on the heat conductivity of the tested compound. This temperature gradient in rotor type curemeters is compared to rotorless curemeters. It is shown that using the unfilled EPDM/DCP compound for temperature calibration leads to a too high effective temperature for filled compounds.

Computation of Temperature Distribution in Infiltration of Metal in Opal Using a Graphite Furnace Heating Assembly

2005 ◽  
Vol 878 ◽  
Author(s):  
Hossein Golnabi ◽  
Mahmood Ghorannevis ◽  
Nahid Chaboki
Keyword(s):  
High Temperature ◽  
Temperature Distribution ◽  
Temperature Dependence ◽  
Heat Conductivity ◽  
Graphite Furnace ◽  
Equilibrium Studies ◽  
Infiltration Process ◽  
High Temperature Furnace ◽  
Melt Infiltration ◽  
Temperature Furnace

AbstractThe use of high temperature furnace assembly used in high–temperature high-pressure machine is proposed and modeled for the infiltration process of metals in opals. The goal here is to provide useful information about the temperature distribution inside the capsule cell in order to save some time and reduce synthesis cost in the real infiltration process. The heat conduction equation is solved for a cylindrical geometry and the variation of the temperature as a function of time and radius distance are reported. The 2-D finite element method for a symmetrical assembly is used and the temperature dependence of heat conductivity of multi elements is considered in the calculations. Temperature dependence of heat conductivity of different elements involved in infiltration process are modeled and also reported here. Such information concerning the temperature distribution inside the infiltration assembly is helpful for both the equilibrium studies and transient conditions. Results of such study help the users to properly select the appropriate temperature gradient for the steady state and transient situations. Such temperature and pressure adjustments are helpful for a successful melt infiltration process.

Stochastic Analysis of Temperature Distribution in a Solid With Random Heat Conductivity

1988 ◽  
Vol 110 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Da Yu Tzou
Keyword(s):  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Heat Conductivity ◽  
Stochastic Analysis ◽  
Solid Medium ◽  
Mean Value ◽  
Random Response ◽  
Thermal Failure ◽  
Numerical Examples ◽  
The Mean

Stochastic temperature distribution in a solid medium with random heat conductivity is investigated by the method of perturbation. The intrinsic randomness of the thermal conductivity k(x) is considered to be a distribution function with random amplitude in the solid, and several typical stochastic processes are considered in the numerical examples. The formulation used in the present analysis describes a situation that the statistical orders of the random response of the system are the same as those of the intrinsic random excitations, which is characteristic for the problem with extrinsic randomness. The maximum standard deviation of the temperature distribution from the mean value in the solid medium reveals the amount of unexpected energy experienced by the solid continuum, which should be carefully inspected in the thermal-failure design of structures with intrinsic randomness.

scholarly journals Temperature log simulations in high-enthalpy boreholes

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Jia Wang ◽  
Fabian Nitschke ◽  
Maziar Gholami Korzani ◽  
Thomas Kohl
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Flow Rate ◽  
Fluid Loss ◽  
Flow Conditions ◽  
Flow Rates ◽  
High Enthalpy ◽  
Fluid Losses ◽  
Lateral Heat

Abstract Temperature logs have important applications in the geothermal industry such as the estimation of the static formation temperature (SFT) and the characterization of fluid loss from a borehole. However, the temperature distribution of the wellbore relies on various factors such as wellbore flow conditions, fluid losses, well layout, heat transfer mechanics within the fluid as well as between the wellbore and the surrounding rock formation, etc. In this context, the numerical approach presented in this paper is applied to investigate the influencing parameters/uncertainties in the interpretation of borehole logging data. To this end, synthetic temperature logs representing different well operation conditions were numerically generated using our newly developed wellbore simulator. Our models account for several complex operation scenarios resulting from the requirements of high-enthalpy wells where different flow conditions, such as mud injection with- and without fluid loss and shut-in, occur in the drill string and the annulus. The simulation results reveal that free convective heat transfer plays an important role in the earlier evolution of the shut-in-time temperature; high accuracy SFT estimation is only possible when long-term shut-in measurements are used. Two other simulation scenarios for a well under injection conditions show that applying simple temperature correction methods on the non-shut-in temperature data could lead to large errors for SFT estimation even at very low injection flow rates. Furthermore, the magnitude of the temperature gradient increase depends on the flow rate, the percentage of fluid loss and the lateral heat transfer between the fluid and the rock formation. As indicated by this study, under low fluid losses (< 30%) or relatively higher flow rates (> 20 L/s), the impact of flow rate and the lateral heat transfer on the temperature gradient increase can be ignored. These results provide insights on the key factors influencing the well temperature distribution, which are important for the choice of the drilling data to estimate SFT and the design of the inverse modeling scheme in future studies to determine an accurate SFT profile for the high-enthalpy geothermal environment.

scholarly journals Thermal condition of cohesion in a two-layer roll of a rolling mill

2019 ◽  
pp. 45-48
Author(s):  
Olga Panteleivna Demyanchenko ◽  
Viktor Lyashenko
Keyword(s):  
Heat Exchange ◽  
Temperature Distribution ◽  
Heat Conductivity ◽  
Rolling Mill ◽  
Thermal Condition ◽  
Thermal Contact ◽  
Homogeneous Equation ◽  
Target Setting ◽  
Radial Section ◽  
Ideal Thermal Contact

A condition of heat exchange between the layershaving different thermalphysic properties in a two-layercylindrical roll of a rolling mill is analyzed foe an ideal thermalcontact. It can be realized with application of the condition ofheat balance of one of the layers in the cylindrical area for ahomogeneous equation of heat conductivity. Analyzed was asimplified target setting in the radial section with a supposition,regarding an averaged in radius temperature distribution in theouter layer. By applying the condition of the thermal balance andby integrating the homogeneous equation of heat conductivity inthe two-layer area a condition of cohesion of an impedance typein case of an ideal thermal contact between the layers wasconstructed.

Numerical Simulation of Temperature Distribution in a Containment Vessel of an Operating PWR Plant

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Yoichi Utanohara ◽  
Michio Murase ◽  
Akihiro Masui ◽  
Ryo Inomata ◽  
Yuji Kamiya
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Heat Release ◽  
Gas Phase ◽  
Large Temperature ◽  
Measured Temperature ◽  
Average Temperature ◽  
Containment Vessel ◽  
Large Temperature Gradient

The structural integrity of the containment vessel (CV) for a pressurized water reactor (PWR) plant under a loss-of-coolant accident is evaluated by a safety analysis code that uses the average temperature of gas phase in the CV during reactor operation as an initial condition. Since the estimation of the average temperature by measurement is difficult, this paper addressed the numerical simulation for the temperature distribution in the CV of an operating PWR plant. The simulation considered heat generation of the equipment, the ventilation and air conditioning systems (VAC), heat transfer to the structure, and heat release to the CV exterior based on the design values of the PWR plant. The temperature increased with a rise in height within the CV and the flow field transformed from forced convection to natural convection. Compared with the measured temperature data in the actual PWR plant, predicted temperatures in the lower regions agreed well with the measured values. The temperature differences became larger above the fourth floor, and the temperature inside the steam generator (SG) loop chamber on the fourth floor was most strongly underestimated, −16.2  K due to the large temperature gradient around the heat release equipment. Nevertheless, the predicted temperature distribution represented a qualitative tendency, low at the bottom of the CV and increases with a rise in height within the CV. The total volume-averaged temperature was nearly equal to the average gas phase temperature. To improve the predictive performance, parameter studies regarding heat from the equipment and the reconsideration of the numerical model that can be applicable to large temperature gradient around the equipment are needed.

scholarly journals Temperature drives diversification in a model adaptive radiation

2018 ◽  
Vol 285 (1886) ◽  
pp. 20181515 ◽  
Author(s):  
Quan-Guo Zhang ◽  
Han-Shu Lu ◽  
Angus Buckling
Keyword(s):  
Genetic Variation ◽  
Temperature Gradient ◽  
Temperature Dependence ◽  
Adaptive Radiation ◽  
Low Temperatures ◽  
Energy Availability ◽  
Positive Temperature ◽  
Direct Effects ◽  
Diversifying Selection ◽  
Ancestral Type

The warmer regions harbour more species, attributable to accelerated speciation and increased ecological opportunities for coexistence. While correlations between temperature and energy availability and habitat area have been suggested as major drivers of these biodiversity patterns, temperature can theoretically also have direct effects on the evolution of diversity. Here, we experimentally studied the evolution of diversity in a model adaptive radiation of the bacterium Pseudomonas fluorescens across a temperature gradient. Diversification increased at higher temperatures, driven by both faster generation of genetic variation and stronger diversifying selection. Specifically, low temperatures could limit the generation of diversity, suggested by the observation that supply of genetic variation through immigration increased diversity at low, but not high temperatures. The two major determinants of mutation supply, population size and mutation rate, both showed a positive temperature dependence. Stronger diversifying selection in warmer environments was suggested by promoted coexistence, and further explicitly inferred by the ability of evolved phenotypes to invade the ancestral type from rare. We discuss possible physiological and environmental mechanisms underlying the findings, most of which are likely to be general.

Study on the transient temperature distribution of new conical friction plate under sliding friction

2021 ◽  
pp. 095440702110696
Author(s):  
Yanzhong Wang ◽  
Peng Liu
Keyword(s):  
Temperature Distribution ◽  
Temperature Gradient ◽  
Temperature Rise ◽  
Friction Surface ◽  
Sliding Friction ◽  
Conical Surface ◽  
Transient Temperature ◽  
Radial Temperature Gradient ◽  
Radial Temperature ◽  
Friction Plate

Conical friction surface is a novel configuration for friction plate in transmission. Numerical FEA models for transient heat transfer and distribution of conically grooved friction plate have been established to investigate the thermal behavior of the conical surface with different configurations. The finite element method is used to obtain the numerical solution, the temperature test data of conical surface are obtained by the friction test rig. In order to study and compare the temperature behavior of conically grooved friction plate, several three-dimensional transient temperature models are established. The heat generated on the friction interface during the continuous sliding process is calculated. Two different pressure conditions were defined to evaluate the influence of different load conditions on temperature rise and the effects of conical configuration parameters on surface temperature distribution are investigated. The results show that the radial temperature gradient on conical friction surface is obvious. The uniform pressure condition could be used when evaluating the temperature rise of conically grooved friction plate. The increase of the cone height could improve the radial temperature gradient of the conically grooved friction plate.

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