Estimation of Creep Buckling Deformation Under External Pressure at Elevated Temperature

1996 ◽  
Vol 118 (2) ◽  
pp. 194-197 ◽  
Author(s):  
Y. Kaji ◽  
I. Ioka ◽  
I. Nishiguchi ◽  
Y. Miyamoto
Keyword(s):  
Heat Transfer ◽  
Elevated Temperature ◽  
External Pressure ◽  
Pressure Level ◽  
Collapse Time ◽  
Transfer Tube ◽  
Simplified Method ◽  
Creep Buckling ◽  
Leak Tightness ◽  
Pass Through

The effect of the initial ovality, wall thickness, and pressure level on the collapse time of a heat transfer tube subjected to both constant and cycled external pressure at elevated temperature was examined experimentally and analytically. The creep deformation of the tube obtained by FEM code and the simplified method was a good approximation. The simplified method proposed by Nishiguchi et al. is an effectual method in the estimation of the creep buckling deformation and the collapse time of the tube under external pressure at elevated temperature as compared with the experimental results and the FEM. Though many cracks initiated by creep collapse were observed on the outer surface of a few test tubes, the cracks did not pass through the tube thickness, and leak tightness was maintained despite a collapse for all tubes tested.

A Creep Buckling Design Method of Elliptical Heads Based on the External Pressure Chart

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Fang Liu ◽  
Jian-Guo Gong ◽  
Fu-Hai Gao ◽  
Fu-Zhen Xuan
Keyword(s):  
Design Method ◽  
External Pressure ◽  
Design Approach ◽  
Design Criteria ◽  
Design Factor ◽  
Simplified Method ◽  
Creep Buckling ◽  
Conservative Result

The buckling design criteria of elliptical heads in ASME VIII-1, ASME NH, and RCC-MRx are reviewed and compared. Accordingly, an external pressure chart (EPC) based buckling design approach is developed for elliptical heads in the creep range. Results indicate that for instantaneous buckling design, RCC-MRx predicts higher allowable pressure compared with ASME NH, which is ascribed to the smaller design factor. The proposed method produces a similar result with that given by ASME VIII-1. By contrast, the proposed method leads to a reasonably conservative result with the factor n of 0.03 for the creep buckling design. While the simplified method in RCC-MRx provides an over-conservative solution.

Impingement Cooling Flow and Heat Transfer Under Acoustic Excitations

1997 ◽  
Vol 119 (4) ◽  
pp. 810-817 ◽  
Author(s):  
C. Gau ◽  
W. Y. Sheu ◽  
C. H. Shen
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Shear Layer ◽  
Turbulence Intensity ◽  
Pressure Level ◽  
Unstable Wave ◽  
Impingement Cooling ◽  
Cooling Flow ◽  
Acoustic Excitations ◽  
Excitation Pressure

Experiments are performed to study (a) slot air jet impingement cooling flow and (b) the heat transfer under acoustic excitations. Both flow visualization and spectral energy evolution measurements along the shear layer are made. The acoustic excitation at either inherent or noninherent frequencies can make the upstream shift for both the most unstable waves and the resulting vortex formation and its subsequent pairing processes. At inherent frequencies the most unstable wave can be amplified, which increases the turbulence intensity in both the shear layer and the core and enhances the heat transfer. Both the turbulence intensity and the heat transfer increase with increasing excitation pressure levels Spl until partial breakdown of the vortex occurs. At noninherent frequencies, however, the most unstable wave can be suppressed, which reduces the turbulence intensity and decreases the heat transfer. Both the turbulence intensity and the heat transfer decreases with increasing Spl, but increases with increasing Spl when the excitation frequency becomes dominant. For excitation at high Reynolds number with either inherent or noninherent frequency, a greater excitation pressure level is needed to cause the enhancement or the reduction in heat transfer. During the experiments, the inherent frequencies selected for excitation are Fo/2 and Fo/4, the noninherent frequencies are 0.71 Fo, 0.75 Fo, and 0.8 Fo, the acoustic pressure level varies from 70 dB to 100 dB, and the Reynolds number varies from 5500 to 22,000.

scholarly journals Numerical Analysis on Rib-Tubes of Seawater Open Rack Vaporizer With the Spoiler Lever

2017 ◽  
Vol 24 (s2) ◽  
pp. 14-21
Author(s):  
Su Houde ◽  
Yu Shurong ◽  
Fan Jianling ◽  
Wei Xing
Keyword(s):  
Heat Transfer ◽  
Tube Wall ◽  
Small Difference ◽  
Operating Temperature ◽  
Operating Parameter ◽  
Tube Model ◽  
Heat Transfer Tube ◽  
Transfer Tube ◽  
Gasification Efficiency ◽  
Gas Ratio

Abstract In order to explore a more reasonable structure and operating parameter, guide the design and improve the gasification of seawater Open Rack Vaporizer (ORV), Research on the rules of seawater that flows and heat transfer in the ORV tube was studied in this paper. By simplifying the model, heat transfer tube model with spoiler lever was obtained and simulated, the distribution of temperature field, gas ratio, velocity field and press field in rib tube were analyzed, and different inlet velocity of LNG, roughness of the tube wall both effected on the overall gasification, the results shows that the actual gasification efficiency from heat transfer tube is higher than normal, small difference of gas ratio outlet, velocity and temperature are both lower, LNG could be easer gasified at operating temperature between -162°C~+3°C than that between -162°C~+0°C.

Gas hydrate fast nucleation from melting ice and quiescent growth along vertical heat transfer tube

2005 ◽  
Vol 48 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Yingming Xie ◽  
Kaihua Guo ◽  
Deqing Liang ◽  
Shuanshi Fan ◽  
Jianming Gu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Hydrate ◽  
Heat Transfer Tube ◽  
Transfer Tube ◽  
Vertical Heat

scholarly journals Heat Transfer and Slip Effects on the Mhd Peristaltic Flow of Viscous Fluid in A Tapered Microvessels: Application of Blood Flow Research

2019 ◽  
Vol 9 (1) ◽  
pp. 5384-5390
Keyword(s):  
Heat Transfer ◽  
Blood Flow ◽  
Research Work ◽  
Flow Characteristics ◽  
Peristaltic Flow ◽  
Pressure Level ◽  
Slip Parameter ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Slip Effects

This research work is proposed at reporting heat transfer on the peristaltic flow of an electrically conducting fluid in a tapered microvessels under the lubrication theory. The proposed geometry analyzes the blood flow in the heart vessels and maintain the pressure level in the human body. The solutions for the distribution of axial velocity, temperature distribution, pressure gradient and stream function have been obtained analytically. The influences of many evolving parameters on the flow characteristics are revealed and deliberated with the assist of figures. The mathematical outcomes show that the trapped bolus enhances in size with increasing slip parameter but decreases with the increase of Grashof number.

Comparative studies of energy saving polymers and fabrication of high performance transparent polymer by solvent bonding

2018 ◽  
Vol 39 (1) ◽  
pp. 68-75
Author(s):  
S.P. Aadhy ◽  
T. Hema Sinega ◽  
C. Karthikeyan ◽  
S. Akshay ◽  
Mohan Kumar Pitchan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
High Performance ◽  
Solvent Mixture ◽  
Heat Transfer Analysis ◽  
Compression Moulding ◽  
Lap Shear ◽  
Visible Wavelengths ◽  
Pass Through ◽  
Solvent Bonding

Abstract This work investigates the possibility of using polyetherimide (PEI) as an energy saving alternative to glass, polymethylmethacrylate (PMMA) and polycarbonate (PC) by carrying out heat transfer analysis and suggests vaporized solvent bonding as a viable bonding technique for the fabrication of PEI. By heat transfer analysis using building energy simulation, it is observed that less energy is expended for space-conditioning of a building with windows made of PEI when compared to glass, PMMA and PC. The compression moulding technique is used to mould PEI and fabrication is done using a solvent mixture of dimethyl sulfoxide and tetrahydrofuran in 1:1 ratio. The optical properties of the bonded specimen are studied using UV-visible spectrophotometry and it is found that PEI does not allow UV wavelength radiation to pass through while transmitting visible wavelengths. The mechanical strength of the bond is tested using lap shear tensile strength test and the type of failure is observed to be cohesive from the structure. This is indicative of the fact that using this particular solvent to bond PEI results in the maximum possible strength.

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