scholarly journals The transient response for different types of erodable surface thermocouples using finite element analysis

2007 ◽  
Vol 11 (4) ◽  
pp. 49-64 ◽  
Author(s):  
Hussein Mohammed ◽  
Hanim Salleh ◽  
Mohd Yusoff
Keyword(s):  
Finite Element Analysis ◽  
Heat Flux ◽  
Thermal Properties ◽  
Surface Temperature ◽  
Transient Response ◽  
Temperature History ◽  
Two Dimensional ◽  
Flux Variation ◽  
Element Analysis ◽  
Different Types

The transient response of erodable surface thermocouples has been numerically assessed by using a two dimensional finite element analysis. Four types of base metal erodable surface thermocouples have been examined in this study, included type-K (alumel-chromel), type-E (chromel-constantan), type-T (copper-constantan), and type-J (iron-constantan) with 50 mm thick- ness for each. The practical importance of these types of thermocouples is to be used in internal combustion engine studies and aerodynamics experiments. The step heat flux was applied at the surface of the thermocouple model. The heat flux from the measurements of the surface temperature can be commonly identified by assuming that the heat transfer within these devices is one-dimensional. The surface temperature histories at different positions along the thermocouple are presented. The normalized surface temperature histories at the center of the thermocouple for different types at different response time are also depicted. The thermocouple response to different heat flux variations were considered by using a square heat flux with 2 ms width, a sinusoidal surface heat flux variation width 10 ms period and repeated heat flux variation with 2 ms width. The present results demonstrate that the two dimensional transient heat conduction effects have a significant influence on the surface temperature history measurements made with these devices. It was observed that the surface temperature history and the transient response for thermocouple type-E are higher than that for other types due to the thermal properties of this thermocouple. It was concluded that the thermal properties of the surrounding material do have an impact, but the properties of the thermocouple and the insulation materials also make an important contribution to the net response.

Transient response of an erodable heat flux gauge using finite element analysis

2002 ◽  
Vol 216 (8) ◽  
pp. 701-706 ◽  
Author(s):  
D R Buttsworth
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Surface Temperature ◽  
Transient Response ◽  
Transient Heat Conduction ◽  
Two Dimensional ◽  
Element Analysis ◽  
Ic Engine ◽  
One Dimensional ◽  
Transient Heat Flux

The transient response of an erodable ribbon element heat flux gauge has been assessed using a two-dimensional finite element (FE) analysis. Such transient heat flux gauges have previously been used for measurements in internal combustion (IC) engines. To identify the heat flux from the measurements of surface temperature, it is commonly assumed that the heat transfer within these devices is one-dimensional. A corollary of the one-dimensional treatment is that only one value of the thermal product, , is needed for identification of the transient heat flux, even though erodable heat flux gauges are constructed from at least two different materials. The current results demonstrate that two-dimensional transient heat conduction effects have a significant influence on the surface temperature measurements made with these devices. For the ribbon element gauge and timescales of interest in IC engine studies, using a one-dimensional analysis (and hence a single value of ) will lead to substantial inaccuracy in the derived heat flux measurements.

An Influence of a Shape of a Flaw on a Value of Stress on Beams

2016 ◽  
Vol 837 ◽  
pp. 230-233
Author(s):  
Janka Kovacikova ◽  
Olga Ivankova ◽  
Dusan Drobny
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Main Topic ◽  
Two Dimensional ◽  
Bottom Edge ◽  
Element Analysis ◽  
Central Crack ◽  
A Value ◽  
Different Types

The main topic of this paper is finite element analysis of 4-point loaded glulam beams which contain different types of flaws. There were modeled four types of beams. First type was the beam without a flaw, second was the beam with a central crack in the middle of span located at the bottom edge of the beam, third model of beams contained also the central crack but this crack was located 20 mm above the edge and the last model contained a hole in the middle of the span as simulation of a knot. These models were performed and analyzed in ANSYS. Task was considered as two dimensional. There were compared values of stress in different types of beam's models.

Two-Dimensional Full-Vectorial Finite Element Analysis of NRD Guide Devices

2021 ◽  
Vol 31 (4) ◽  
pp. 345-348
Author(s):  
Yasuhide Tsuji ◽  
Keita Morimoto ◽  
Akito Iguchi ◽  
Tatsuya Kashiwa ◽  
Shinji Nishiwaki
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Two Dimensional ◽  
Element Analysis ◽  
Nrd Guide

Thermal Modeling of a Railroad Tapered-Roller Bearing Using Finite Element Analysis

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Constantine M. Tarawneh ◽  
Arturo A. Fuentes ◽  
Javier A. Kypuros ◽  
Lariza A. Navarro ◽  
Andrei G. Vaipan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Surface Temperature ◽  
Elevated Temperatures ◽  
Roller Bearing ◽  
Fe Model ◽  
Element Analysis ◽  
Tapered Roller Bearing ◽  
Outer Race ◽  
Railroad Industry

In the railroad industry, distressed bearings in service are primarily identified using wayside hot-box detectors (HBDs). Current technology has expanded the role of these detectors to monitor bearings that appear to “warm trend” relative to the average temperatures of the remainder of bearings on the train. Several bearings set-out for trending and classified as nonverified, meaning no discernible damage, revealed that a common feature was discoloration of rollers within a cone (inner race) assembly. Subsequent laboratory experiments were performed to determine a minimum temperature and environment necessary to reproduce these discolorations and concluded that the discoloration is most likely due to roller temperatures greater than 232 °C (450 °F) for periods of at least 4 h. The latter finding sparked several discussions and speculations in the railroad industry as to whether it is possible to have rollers reaching such elevated temperatures without heating the bearing cup (outer race) to a temperature significant enough to trigger the HBDs. With this motivation, and based on previous experimental and analytical work, a thermal finite element analysis (FEA) of a railroad bearing pressed onto an axle was conducted using ALGOR 20.3™. The finite element (FE) model was used to simulate different heating scenarios with the purpose of obtaining the temperatures of internal components of the bearing assembly, as well as the heat generation rates and the bearing cup surface temperature. The results showed that, even though some rollers can reach unsafe operating temperatures, the bearing cup surface temperature does not exhibit levels that would trigger HBD alarms.

Heat transfer at the step of a CANDU calandria during a severe accident

Kerntechnik ◽  
2021 ◽  
Vol 86 (5) ◽  
pp. 338-342
Author(s):  
R. David
Keyword(s):  
Heat Transfer ◽  
Finite Element Analysis ◽  
Heat Flux ◽  
Annular Plate ◽  
Welded Joint ◽  
Severe Accident ◽  
Local Concentration ◽  
Element Analysis ◽  
Surrounding Water ◽  
Decay Heat

Abstract During the in-vessel stage of a severe accident in a CANDU 6 reactor, decay heat from a collapsed core would be rejected through the calandria walls into the surrounding water. At the step in the calandria wall, the subshell and annular plate meet at a right angle pointing into the calandria. The geometry at this joint could concentrate the exiting heat flux, potentially leading to calandria failure. Finite element analysis is used to study the heat transfer near the welded joint. Different weld profiles, boundary conditions, and decay heat characteristics are considered, and the local concentration of exiting heat flux is calculated.

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