TRANSIENT TEMPERATURE DISTRIBUTION IN ROTARY REGENERATOR HEAT EXCHANGER

1993 ◽  
Vol 3 (2) ◽  
pp. 173-182 ◽  
Author(s):  
ITSURO SAKAI ◽  
YOSHIHIRO KAWAGUCHI
Keyword(s):  
Heat Exchanger ◽  
Temperature Distribution ◽  
Transient Temperature ◽  
Transient Temperature Distribution

Determination of Temperature Limits for Heat Exchanger Joint Assembled of Solid Stainless Tubesheet With Girth Flanges

2017 ◽  
Author(s):  
Bassel Y. Mohamed ◽  
Mohamed A. Hamdy ◽  
Tamer I. Eid
Keyword(s):  
Heat Exchanger ◽  
Temperature Distribution ◽  
Heat Exchangers ◽  
Transient Analysis ◽  
Transient Temperature ◽  
Heating Rates ◽  
Element Analysis ◽  
Transient Temperature Distribution ◽  
Steel Heat

Although heat exchangers are built according to international codes and proved to be leak tight by hydrotesting at ambient temperature, leak of stainless steel heat exchangers girth flanges at the tubesheet gaskets likely occurs during startup and operation at high temperatures. Accordingly, evaluation of the design to assure leak free operation considering anticipated thermal events is required. WRC 510 bulletin [4] introduces a simplified analytical method to address this issue and provides safe guarding against leakage. This study is performed on solid 300 series stainless stationary tubesheet flanged with girth flanges having the same or different material of construction. A thermal finite element analysis is performed to obtain the transient temperature distribution through a girth flanges and stationary tubesheet assembly of a heat exchanger using SOLIDWORKS® SIMULATION [7]. The model of the flanged joint consists of two girth flanges with a tubesheet and gaskets in between. Thermal time dependent transient analysis of the above model is conducted to compute the temperature distribution in the flanged joint assembly for different time steps. Further, these temperature distributions are used to compute the expansion, deflection and rotation for the flanged joint parts using WRC 510 bulletin [4] equations. The study determines both the permissible heating rates during startup and the temperature limits, for the example studied, which are suitable for using solid 300 series stainless tubesheet for both material types of the girth flanges to have the most leak tight & economical assembly when the minimum design metal temperature allows these materials.

Direct observation of three-dimensional transient temperature distribution in SiC Schottky barrier diode under operation by optical-interference contactless thermometry (OICT) imaging

2022 ◽  
Author(s):  
Keiya Fujimoto ◽  
Hiroaki Hanafusa ◽  
Takuma Sato ◽  
Seiichiro HIGASHI
Keyword(s):  
Temperature Distribution ◽  
Schottky Barrier ◽  
Hot Spot ◽  
Local Heating ◽  
Three Dimensional ◽  
Schottky Barrier Diode ◽  
Transient Temperature ◽  
Optical Interference ◽  
Transient Temperature Distribution ◽  
Heating And Cooling

Abstract We have developed optical-interference contactless thermometry (OICT) imaging technique to visualize three-dimensional transient temperature distribution in 4H-SiC Schottky barrier diode (SBD) under operation. When a 1 ms forward pulse bias was applied, clear variation of optical interference fringes induced by self-heating and cooling were observed. Thermal diffusion and optical analysis revealed three-dimensional temperature distribution with high spatial (≤ 10 μm) and temporal (≤ 100 μs) resolutions. A hot spot that signals breakdown of the SBD was successfully captured as an anormal interference, which indicated a local heating to a temperature as high as 805 K at the time of failure.

Measurement of Transient Temperature Distribution at Anode Surface After Current Zero in Vacuum Interrupter

2021 ◽  
Vol 141 (11) ◽  
pp. 712-717
Author(s):  
Akira Daibo ◽  
Yoshimitsu Niwa ◽  
Naoki Asari ◽  
Wataru Sakaguchi ◽  
Yo Sasaki ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Anode Surface ◽  
Transient Temperature ◽  
Vacuum Interrupter ◽  
Transient Temperature Distribution ◽  
Current Zero

scholarly journals Exact Solution of Heat Transport Equation for a Heterogeneous Geothermal Reservoir

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2935 ◽  
Author(s):  
Sayantan Ganguly
Keyword(s):  
Temperature Distribution ◽  
Transport Equation ◽  
Heat Transport ◽  
Transport Processes ◽  
Geothermal Reservoir ◽  
Transient Temperature ◽  
Thermal Front ◽  
Transient Temperature Distribution ◽  
Heat Transport Equation ◽  
Geothermal Aquifer

An exact integral solution for transient temperature distribution, due to injection-production, in a heterogeneous porous confined geothermal reservoir, is presented in this paper. The heat transport processes taken into account are advection, longitudinal conduction and conduction to the confining rock layers due to the vertical temperature gradient. A quasi 2D heat transport equation in a semi-infinite porous media is solved using the Laplace transform. The internal heterogeneity of the geothermal reservoir is expressed by spatial variation of the flow velocity and the effective thermal conductivity of the medium. The model results predict the transient temperature distribution and thermal-front movement in a geothermal reservoir and the confining rocks. Another transient solution is also derived, assuming that longitudinal conduction in the geothermal aquifer is negligible. Steady-state solutions are presented, which determine the maximum penetration of the cold water thermal front into the geothermal aquifer.

scholarly journals Heat transfer on simplified pre-period stage of tunnel fire

2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 799-808
Author(s):  
Hungwei Liu ◽  
Wei Yao
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Heating Rate ◽  
Theoretical Solution ◽  
Theoretical Equation ◽  
Thermal Engineering ◽  
Transient Temperature ◽  
Tunnel Fire ◽  
Transient Temperature Distribution ◽  
Heat Transfer Theory

Tunnel fire is a part of applied thermal problems. With increase of transient temperature of the tunnel fire on the structure surface (i.e. tunnel lining), the heat transfer from the surface is possibly varying transient temperature distribution within the structure. The transient temperature distribution is also possibly damaging the composition of structure (micro-crack) because of critical damage temperature. Therefore, the transient temperature distribution has a significantly important role on defining mechanical and physical properties of structure and determining thermal-induced damaged region. The damage at pre-period stage of tunnel fire is perhaps more significant than that at the other period stages because of thermal gradient. Consequently, a theoretical model was developed for simplifying complicated thermal engineering during pre-period stage of tunnel fire. A hollow solid model (HSM) in a combination of dimensional analysis and heat transfer theory with Bessel?s Function and Duhamel?s Theorem were employed to verify a theoretical equation for dimensionless transient temperature distribution (DTTD) under linear transient thermal loading (LTTL). Experimental and numerical methods were also adopted to approve the results from this theoretical equation. The heating rate (M) is a primary variable for discussing DTTD on three means. The heating rate of 10.191, 10 and 240?C/min were applied to experimental and numerical studies. The experimental and numerical results are consistent with the theoretical solution, successfully verifying that the theoretical solution can predict the DTTD well in field. This equation can be used for thermal/tunnel engineers to evaluate the damaged region and to obtain the parameters related to DTTD.

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