scholarly journals MEASUREMENT OF HEAT GENERATION RATE OF HIGHLY RADIOACTIVE CALCINED ALUMINA

1965 ◽  
Author(s):  
D.W. Rhodes ◽  
M.E. Jacobson
Keyword(s):  
Heat Generation ◽  
Generation Rate ◽  
Heat Generation Rate

A novel heat generation acquisition method of cylindrical battery based on core and surface temperature measurements

2021 ◽  
pp. 1-17
Author(s):  
Xiaoli Yu ◽  
Qichao Wu ◽  
Rui Huang ◽  
Xiaoping Chen
Keyword(s):  
Surface Temperature ◽  
Heat Generation ◽  
Discharge Rate ◽  
Total Heat ◽  
Temperature Measurements ◽  
Generation Rate ◽  
Air Cooling ◽  
Heat Generation Rate ◽  
Environmental Chamber ◽  
Average Heat

Abstract Heat generation measurements of the lithium-ion battery are crucial for the design of the battery thermal management system. Most previous work uses the accelerating rate calorimeter (ARC) to test heat generation of batteries. However, utilizing ARC can only obtain heat generation of the battery operating under the adiabatic condition, deviating from common operation scenarios with heat dissipation. Besides, using ARC is difficult to measure heat generation of the high-rate operating battery because the battery temperature easily exceeds the maximum safety limit. To address these problems, we propose a novel method to obtain heat generation of cylindrical battery based on core and surface temperature measurements and select the 21700 cylindrical battery as the research object. Based on the method, total heat generation at 1C discharge rate under the natural convection air cooling condition in the environmental chamber is about 3.2 kJ, and the average heat generation rate is about 0.9 W. While these two results measured by ARC are about 2.2 kJ and 0.6 W. This gap also reflects that different battery temperature histories have significant impacts on heat generation. In addition, using our approach, total heat generation at 2C discharge rate measured in the environmental chamber is about 5.0 kJ, with the average heat generation rate being about 2.8 W. Heat generation results obtained by our method are approximate to the actual battery operation and have advantages in future applications.

Enhancement of Forced Convection Heat Transfer Using Twisted Heater With Exponential Heat Inputs

2013 ◽  
Author(s):  
Makoto Shibahara ◽  
Qiusheng Liu ◽  
Katsuya Fukuda
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heat Generation ◽  
Swirling Flow ◽  
Generation Rate ◽  
Transient Heat Transfer ◽  
Heat Generation Rate ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Plate Heater

Forced convection transient heat transfer coefficients have been measured for nitrogen gas flowing over a twisted heater due to exponentially increasing heat inputs (Q0exp(t/τ)). And then, the effect of heater configuration on transient heat transfer by a twisted heater has been investigated comparing to that of the plate heater. In the experiment, the platinum ribbon with a thickness of 0.1 mm and a width of 4.0 mm was used as a test heater. For heat transfer enhancements in single-phase flow, it was twisted at the central part of the heater with an angle of 90 degrees with respect to the upper part of the heater. The heat generation rate was exponentially increased with a function of Q0exp(t/τ). The gas flow velocity ranged from 1 to 4 m/s for the gas temperatures of 313K. The periods of heat generation rate ranged from 46 ms to 17 s. The surface temperature difference and heat flux increased exponentially as the heat generation rate increased with the exponential function. The heat transfer coefficients for twisted heater have been compared to those of the plate heater. They were 24 % higher than those of the plate one. The geometric effect (twisted effect) of heater in this study showed an enhancement on the heat transfer coefficient. It was considered that the heat transfer coefficients are affected by the change in the flow due to swirling flow on the twisted heater. Finally, the empirical correlations for quasi-steady-state heat transfer and transient one have been obtained based on the experimental data.

A Comparative Analysis of the Tumor Pathology and the Metabolic Heat Generation of Growing Malignant Tumors

2020 ◽  
Author(s):  
Alyssa Owens ◽  
Manasi Godbole ◽  
Donnette Dabydeen ◽  
Lori Medeiros ◽  
Pradyumna Phatak ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Heat Generation ◽  
Infrared Imaging ◽  
Malignant Tumors ◽  
Blood Perfusion ◽  
The United States ◽  
Generation Rate ◽  
Heat Generation Rate ◽  
Clinical Patient ◽  
Tumor Pathology

Abstract Cancer is one of the most debilitating diseases in the world, affecting over 9.6 million people worldwide every year. Breast cancer remains the second largest cause of death in women. Despite major advances in treatment, over 40,920 women died of breast cancer in 2018 in the United States alone. Early detection of abnormal masses can be crucial for diagnosis and dramatically increase survival. Current screening techniques have varying accuracy and perform poorly when used on heterogeneously and extremely dense breast tissue. Infrared imaging has the potential to detect growing tumors within the breast based on thermal signatures on the breast surface by imaging temperature gradients induced by blood perfusion and tumor metabolic activity. Using clinical patient images, previous methods to estimate tumor properties involve an iterative algorithm to estimate the tumor position and diameter. The details from the MRI are used in estimating the volumetric heat generation rate. This is compared with the published values and the reasons for differences are investigated. The tumor pathology is used in estimating the expected growth rate and compared with the predicted values. The correlation between the tumor characteristics and heat generation rate is fundamental information that is needed in accurately predicting the tumor size and location.

Effect of Heater Configurations on Transient Heat Transfer for Various Gases Flowing Over a Twisted Heater

2009 ◽  
Author(s):  
Makoto Shibahara ◽  
Qiusheng Liu ◽  
Katsuya Fukuda
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Generation ◽  
Gas Flow ◽  
Generation Rate ◽  
Transient Heat Transfer ◽  
Heat Generation Rate ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Forced convection transient heat transfer coefficients were measured for helium gas and carbon dioxide gas flowing over a twisted heater due to exponentially increasing heat input (Q0exp(t/τ)). The twisted platinum plate with a thickness of 0.1 mm was used as test heater and heated by electric current. The heat generation rate was exponentially increased with a function of Q0exp(t/τ). The gas flow velocities ranged from 1 to 10 m/s, the gas temperatures ranged from 313 to 353 K, and the periods of heat generation rate ranged from 46 ms to 17 s. The surface temperature difference and heat flux increase exponentially as the heat generation rate increases with the exponential function. Transient heat transfer coefficients increase with increasing gas flow velocity. The geometric effect of twisted heater in this study shows an enhancement on the heat transfer coefficient. Empirical correlation for quasi-steady-state heat transfer was obtained based on the experimental data. The data for heat transfer coefficient were compared with those reported in authors’ previous paper.

Temperature Prediction of a Used Nuclear Fuel Cask With Different Gas Backfills

2020 ◽  
Author(s):  
Megan Higley ◽  
Mustafa Hadj-Nacer ◽  
Miles Greiner
Keyword(s):  
Heat Generation ◽  
Temperature Jump ◽  
Generation Rate ◽  
Spent Fuel ◽  
Heat Generation Rate ◽  
Ansys Fluent ◽  
Used Nuclear Fuel ◽  
Computational Fluid Dynamics Cfd ◽  
Project Lead ◽  
Low Pressures

Abstract In this work, a two-dimensional (2D) geometrically-accurate model of the TN-32 cask is generated in ANSYS/Fluent to investigate the effect of backfill gases and their pressures on the peak cladding temperature (PCT). This model is similar to the cask being used in high-burnup (HBU) spent fuel data project lead by the Electric Power Research Institute (EPRI). Helium, nitrogen, argon, and water vapor fill gases are investigated at pressures ranging from atmospheric (∼105 Pa) to 100 Pa. Steady-state computational fluid dynamics (CFD) simulations that include the effect of gas rarefaction (temperature-jump) at the gas-solid interfaces are conducted. The PCT as a function of heat generation rate and pressure is reported as well as the heat generation rate that brings the cladding temperature to the radial hydride formation limit. The results show that there are competing effects between the temperature-jump and the thermal conductivity of the gas to increase the fuel rods’ temperature. The low pressures increased the PCT, with the increase being most significant for the helium backfill.

Numerical Investigation of Heat Transfer in Tissues During Therapeutic Hyperthermia

2018 ◽  
Author(s):  
Saeed Tiari ◽  
Mahboobe Mahdavi ◽  
Kinjalkumar Chauhan ◽  
Davide Piovesan
Keyword(s):  
Heat Generation ◽  
Thermal Response ◽  
Generation Rate ◽  
Heat Generation Rate ◽  
Hyperthermia Treatment ◽  
Ansys Fluent ◽  
Normal Tissues ◽  
Cooling Conditions ◽  
Magnetic Nanoparticle Hyperthermia ◽  
The Impact

A numerical analysis is conducted to study the thermal behavior of human healthy and cancerous tissues during magnetic nanoparticle hyperthermia treatment. A transient multi-layer two-dimensional model is developed using commercial CFD package, ANSYS-FLUENT 18.1. The impact of therapeutic heat generation rate and various tissue cooling conditions on the thermal response of the tumor and normal tissues are investigated. It was found that the tumor temperature is not affected by different cooling conditions while the temperature of healthy tissues around tumor is significantly impacted. The results also demonstrated that the effective tumor temperature can be achieved in approximately ten minutes by using therapeutic heat generation rate of 150 kW/m3 in all three cooling conditions.

scholarly journals A Parametric Study of the Effects of Critical Design Parameters on the Performance of Nanoscale Silicon Devices

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1987
Author(s):  
Faraz Kaiser Malik ◽  
Tariq Talha ◽  
Faisal Ahmed
Keyword(s):  
Heat Generation ◽  
Initial Temperature ◽  
Scattering Length ◽  
Monte Carlo Model ◽  
Generation Rate ◽  
Design Parameters ◽  
Heat Generation Rate ◽  
Short Channel ◽  
Critical Design ◽  
Silicon Devices

The current electronics industry has used the aggressive miniaturization of solid-state devices to meet future technological demands. The downscaling of characteristic device dimensions into the sub-10 nm regime causes them to fall below the electron–phonon scattering length, thereby resulting in a transition from quasi-ballistic to ballistic carrier transport. In this study, a well-established Monte Carlo model is employed to systematically investigate the effects of various parameters such as applied voltage, channel length, electrode lengths, electrode doping and initial temperature on the performance of nanoscale silicon devices. Interestingly, from the obtained results, the short channel devices are found to exhibit smaller heat generation, with a 2 nm channel device having roughly two-thirds the heat generation rate observed in an 8 nm channel device, which is attributed to reduced carrier scattering in the ballistic transport regime. Furthermore, the drain contacts of the devices are identified as critical design areas to ensure safe and efficient performance. The heat generation rate is observed to increase linearly with an increase in the applied electric field strength but does not change significantly with an increase in the initial temperature, despite a marked reduction in the electric current flowing through the device.

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