Characterization of ceiling smoke temperature profile and maximum temperature rise induced by double fires in a natural ventilation tunnel

2020 ◽  
Vol 96 ◽  
pp. 103233 ◽  
Author(s):  
Qiang Wang ◽  
Shaoming Wang ◽  
Huan Liu ◽  
Jiaying Shen ◽  
Fengju Shang ◽  
...  
Keyword(s):  
Temperature Profile ◽  
Temperature Rise ◽  
Natural Ventilation ◽  
Maximum Temperature ◽  
Maximum Temperature Rise

Modeling temperature rise in multi-track reciprocating frictional sliding

2021 ◽  
pp. 135065012098823
Author(s):  
Thierry A Blanchet
Keyword(s):  
Temperature Rise ◽  
Peclet Number ◽  
Maximum Temperature ◽  
Uniform Heat Flux ◽  
Heat Accumulation ◽  
Stroke Length ◽  
Péclet Number ◽  
Maximum Temperature Rise ◽  
Rectangular Patch ◽  
Accumulation Effect

As in various manufacturing processes, in sliding tests with scanning motions to extend the sliding distance over fresh countersurface, temperature rise during any pass is bolstered by heating during prior passes over neighboring tracks, providing a “heat accumulation effect” with persisting temperature rises contributing to an overall temperature rise of the current pass. Conduction modeling is developed for surface temperature rise as a function of numerous inputs: power and size of heat source; speed and stroke length, and track increment of scanning motion; and countersurface thermal properties. Analysis focused on mid-stroke location for passes of a square uniform heat flux sufficiently far into the rectangular patch being scanned from the first pass at its edge that steady heat accumulation effect response is adopted, focusing on maximum temperature rise experienced across the pass' track. The model is non-dimensionalized to broaden the applicability of the output of its runs. Focusing on practical “high” scanning speeds, represented non-dimensionally by Peclet number (in excess of 40), applicability is further broadened by multiplying non-dimensional maximum temperature rise by the square root of Peclet number as model output. Additionally, investigating model runs at various non-dimensional speed (Peclet number) and reciprocation period values, it appears these do not act as independent inputs, but instead with their product (non-dimensional stroke length) as a single independent input. Modified maximum temperature rise output appears to be a function of only two inputs, increasing with decreasing non-dimensional values of stroke length and scanning increment, with outputs of models runs summarized compactly in a simple chart.

Braking performance of a novel frictional-magnetic compound disc brake for automobiles

2018 ◽  
Vol 233 (10) ◽  
pp. 2443-2454 ◽  
Author(s):  
Yan Yin ◽  
Jiusheng Bao ◽  
Jinge Liu ◽  
Chaoxun Guo ◽  
Tonggang Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Temperature Rise ◽  
Friction Material ◽  
Maximum Temperature ◽  
Interface Temperature ◽  
Disc Brake ◽  
Braking Performance ◽  
Maximum Temperature Rise ◽  
Disc Brakes ◽  
Braking Torque

Disc brakes have been applied in various automobiles widely and their braking performance has vitally important effects on the safe operation of automobiles. Although numerous researches have been conducted to find out the influential law and mechanism of working condition parameters like braking pressure, initial braking speed, and interface temperature on braking performance of disc brakes, the influence of magnetic field is seldom taken into consideration. In this paper, based on the novel automotive frictional-magnetic compound disc brake, the influential law of magnetic field on braking performance was investigated deeply. First, braking simulation tests of disc brakes were carried out, and then dynamic variation laws and mechanisms of braking torque and interface temperature were discussed. Furthermore, some parameters including average braking torque, trend coefficient and fluctuation coefficient of braking torque, average temperature, maximum temperature rise, and the time corresponding to the maximum temperature rise were extracted to characterize the braking performance of disc brakes. Finally, the influential law and mechanism of excitation voltage on braking performance were analyzed through braking simulation tests and surface topography analysis of friction material. It is concluded that the performance of frictional-magnetic compound disc brake is prior to common brake. Magnetic field is greatly beneficial for improving the braking performance of frictional-magnetic compound disc brake.

Maximum temperature rise of fire plume ejected out of the compartment window with a horizontal eave

2020 ◽  
Vol 44 (8) ◽  
pp. 1108-1117
Author(s):  
Linjie Li ◽  
Zihe Gao ◽  
Yilin Li ◽  
Pai Xu ◽  
Ningyu Zhao ◽  
...  
Keyword(s):  
Temperature Rise ◽  
Maximum Temperature ◽  
Fire Plume ◽  
Maximum Temperature Rise

Maximum Temperature Rise in the Reacted Zone of Electrochemical Devices for Space Applications

2003 ◽  
Vol 125 (2) ◽  
pp. 177-181 ◽  
Author(s):  
Carsie A. Hall, ◽  
Edwin P. Russo ◽  
Calvin Mackie
Keyword(s):  
Diffusion Equation ◽  
Temperature Rise ◽  
Unit Volume ◽  
Heat Diffusion ◽  
Maximum Temperature ◽  
Electrode Temperature ◽  
Discharge Current Density ◽  
Heat Diffusion Equation ◽  
Maximum Temperature Rise ◽  
Electrochemical Devices

A model to predict the temperature rise in the reacted zone of discharging electrochemical devices has been developed. The model assumes that electrode kinetics are fast and concentration gradients are negligible. In the reacted zone, a thermal boundary layer grows, and its thickness is proportional to the reacted zone thickness. In the model, the temperature rise is predicted using the one-dimensional heat diffusion equation for a porous medium. The effective heat capacity per unit volume and effective thermal conductivity are defined as a function of electrode porosity. The instantaneous power per unit area dissipated in the reacted zone is used as a source term in the heat diffusion equation. With fixed parameters such as discharge current density, charge capacity per unit volume, electrode electrical conductivity, electrode porosity, and thermophysical properties of the pore-space fluid and electrode, the transient temperature distribution in the reacted zone is derived in closed-form. Subsequently, the maximum electrode temperature is readily obtained, and the maximum electrode temperature at complete discharge is derived. A new dimensionless parameter, the electro-thermal number, emerges as one of the most important parameters controlling the discharge time and maximum temperature rise.

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