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.

scholarly journals Determination of temperature and thermal stresses distribution in power boiler elements with use inverse heat conduction method

2011 ◽  
Vol 32 (3) ◽  
pp. 191-200 ◽  
Author(s):  
sławomir Grądziel
Keyword(s):  
Boundary Condition ◽  
Heat Conduction ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
Thermal Boundary Condition ◽  
Transient Temperature ◽  
Inverse Heat Conduction ◽  
Transient Temperature Distribution ◽  
Power Boiler

Determination of temperature and thermal stresses distribution in power boiler elements with use inverse heat conduction method The following paper presents the method for solving one-dimensional inverse boundary heat conduction problems. The method is used to estimate the unknown thermal boundary condition on inner surface of a thick-walled Y-branch. Solution is based on measured temperature transients at two points inside the element's wall thickness. Y-branch is installed in a fresh steam pipeline in a power plant in Poland. Determination of an unknown boundary condition allows for the calculation of transient temperature distribution in the whole element. Next, stresses caused by non-uniform transient temperature distribution and by steam pressure inside a Y-branch are calculated using the finite element method. The proposed algorithm can be used for thermal-strength state monitoring in similar elements, when it is not possible to determine a 3-D thermal boundary condition. The calculated temperature and stress transients can be used for the calculation of element durability. More accurate temperature and stress monitoring will contribute to a substantial decrease of maximal stresses that occur during transient start-up and shut-down processes.

Numerical and Experimental Investigations on Deposition of Stainless Steel in Wire Arc Additive Manufacturing

2021 ◽  
Vol 11 (4) ◽  
pp. 40-56
Author(s):  
Ashish Kumar ◽  
Kuntal Maji
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Additive Manufacturing ◽  
Temperature Distribution ◽  
Wall Structure ◽  
Experimental Investigations ◽  
Transient Temperature ◽  
Element Analysis ◽  
Transient Temperature Distribution ◽  
Wire Arc Additive Manufacturing

This paper presents numerical and experimental investigations on wire arc additive manufacturing for deposition of 430L ferritic stainless steel. Finite element analysis was used to predict temperature distribution for deposition of multiple layers in wire arc additive manufacturing. The transient temperature distribution and predicted by finite element simulation was in good agreement with the experimental results. A wall type structure was fabricated by deposition of multiple layers vertically, and deposited material was characterized by tensile testing and microstructure study. The microstructure of the deposited wall structure was investigated through optical microscopy and scanning electron microscopy (SEM) with EDS. The microstructure of deposited material was changed from fine cellular grains structure to columnar dendrites structure with the formation of secondary arm. It was found that the YS, UTS, and EL of the deposition direction were better than the build direction. The mechanical properties of the WAAM manufactured material was found comparable to that of the wire metal.

scholarly journals Steady-state and transient heat transfer through fins of complex geometry

2014 ◽  
Vol 35 (2) ◽  
pp. 117-133 ◽  
Author(s):  
Dawid Taler ◽  
Jan Taler
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Temperature Distribution ◽  
Transient Analysis ◽  
Complex Geometry ◽  
Transient Temperature ◽  
Heat Flow Rate ◽  
Approximate Methods ◽  
Fin Efficiency ◽  
Transient Temperature Distribution

Abstract Various methods for steady-state and transient analysis of temperature distribution and efficiency of continuous-plate fins are presented. For a constant heat transfer coefficient over the fin surface, the plate fin can be divided into imaginary rectangular or hexangular fins. At first approximate methods for determining the steady-state fin efficiency like the method of equivalent circular fin and the sector method are discussed. When the fin geometry is complex, thus transient temperature distribution and fin efficiency can be determined using numerical methods. A numerical method for transient analysis of fins with complex geometry is developed. Transient temperature distributions in continuous fins attached to oval tubes is computed using the finite volume - finite element methods. The developed method can be used in the transient analysis of compact heat exchangers to calculate correctly the heat flow rate transferred from the finned tubes to the fluid.

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
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