Determination of gaseous heat transfer coefficients at elevated temperatures

Giacobbe, F. W.

doi:10.1016/j.applthermaleng.2004.03.004

Cited by 6 publications

(4 citation statements)

References 11 publications

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“…It is verified that the lighter the gas the higher the heat transfer. Moreover it is confirmed that the difference in heat transfer between the two gases is similar to that which was found in [10] where the tested gases were helium (with molecular weight 4 gr/mol) and argon (with molecular weight 40 gr/mol). In this experiment nitrogen has smaller molecular weight (28 gr/mol).…”

supporting

confidence: 70%

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Evaluation of heat transfer coefficient of tungsten filaments at low pressures and high temperatures

Chondrakis

Topalis

2011

Applied Thermal Engineering

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supporting

confidence: 70%

“…where Regarding all this difficulty an overall heat transfer coefficient (h) is usually employed that is estimated experimentally for specific cases [10]. The coefficient h incorporates gaseous heat transfer besides radiation losses.…”

Section: N = H O •A•(t H -T C ) + ε•α•A•(t H 4 -T C 4 )mentioning

confidence: 99%

Evaluation of heat transfer coefficient of tungsten filaments at low pressures and high temperatures

Chondrakis

Topalis

2011

Applied Thermal Engineering

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“…where is the convection heat flux ( / 2 ), ℎ the heat convection coefficient ( / 2 /°) [10] , the temperature of He atmosphere (known to be equal to 30°C). The specimen is initially heated to a central temperature at mid-thickness of 400°C using a low voltage, high current electrical power supply.…”

Section: Heat Transfer Analysesmentioning

confidence: 99%

High cycle thermal fatigue of austenitic stainless steel

et al. 2018

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Abstract.A new experimental setup called FLASH (THErmal Fatigue by LASer or Helium pulses) has been developed to perform thermal fatigue tests on materials used in structures of Sodium-cooled Fast Reactors (SFRs). A set of thermal loadings ranging from 150°C to 200°C prescribed by a high energy laser has been applied to A316L(N) stainless steel samples. Thermal fatigue tests are performed until a macrocrack is formed. The 3D displacement fields of the surface impacted by the laser beam are measured by a hybrid multiview system. A thermomechanical model is used to compute displacement fields that are compared with correlation measurements. These results are compared in terms of strain levels to the fatigue curve determined from standardized isothermal uniaxial mechanical fatigue tests.

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“…The higher the heat transfer coefficient, the higher is the cooling rate of the laser irradiation region. 28) Spatter was generated when metal powder was wound up by the expansion of atmospheric gas that was instantaneously heated to a high temperature in the laser irradiation region and the subsequent generation of an updraft. 29) In addition, the reaction pressure owing to the extreme expansion of gas phase generated a spatter of the metal jet.…”

Section: A D V a N C E V I E Wmentioning

confidence: 99%

Reduction of Spatter Generation Using Atmospheric Gas in Laser Powder Bed Fusion of Ti–6Al–4V

Amano

Yamaguchi²,

Ishimoto

et al. 2021

Mater. Trans.

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Laser powder bed fusion (LPBF), a typical additive manufacturing (AM) process, is a promising approach that enables high-accuracy manufacturing of arbitrary structures; therefore, it has been utilized in the aerospace and medical fields. However, several unexplained phenomena significantly affect the quality of fabricated components. In particular, it has been reported that the generation of spatters adversely affects the stability of fabrication process and degrades the performance of the fabricated components. To realize high-quality components, it is essential to suppress the generation of spatters. Thus far, the suppression of spatter generation has been attempted based on the process parameters; however, this has not been adequately discussed in terms of the fabrication atmosphere. Therefore, in this study, we focused on the fabrication atmosphere and investigated spatter generation using gas with different physical properties rather than conventionally used argon. It was observed that the spatter generation during the fabrication of the Ti6Al4V alloy could be significantly suppressed by changing the atmospheric gas, even under constant LPBF process parameters. We proved that the fabrication atmosphere is an important factor to be considered, apart from the process parameters, in AM technology.

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Determination of gaseous heat transfer coefficients at elevated temperatures

Cited by 6 publications

References 11 publications

Evaluation of heat transfer coefficient of tungsten filaments at low pressures and high temperatures

Evaluation of heat transfer coefficient of tungsten filaments at low pressures and high temperatures

High cycle thermal fatigue of austenitic stainless steel

Reduction of Spatter Generation Using Atmospheric Gas in Laser Powder Bed Fusion of Ti–6Al–4V

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