Thermal Analysis and Strength Evaluation of Cargo Tanks in Offshore FLNGs and LNG Carriers

2013 ◽  
Author(s):  
Bo Wang ◽  
Yong Chen ◽  
Yung-Sup Shin ◽  
Xiaozhi Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Temperature Distribution ◽  
Fe Analysis ◽  
Heat Transfer Analysis ◽  
Fe Model ◽  
Loading Conditions ◽  
Strength Evaluation ◽  
Hull Structure ◽  
Design Loads

The objective of this study is to develop a procedure for thermal analysis and strength evaluation of cargo tank structures in offshore FLNGs and LNG carriers. In this paper, a heat transfer analysis methodology has been employed, and a computational tool has been developed for its application on hull and tank structures in both membrane-type and independent Self-supporting Prismatic type B (SPB) LNG vessels. Using this method, the temperature distribution and corresponding heat transfer coefficients (HTCs) in both the hull structure and void spaces can be estimated so the appropriate steel grade can be selected for the inner hull and the boil-off rate (BOR) can be calculated for LNG vessels. Based on these estimated temperature environmental profiles and HTCs in void spaces, the detailed temperature distribution of an independent SPB tank including the tank boundary and internal structures can be calculated using steady-state thermal FE analysis. Then, the temperature distribution obtained from thermal FE modeling is applied to the FE model as loading conditions for thermal stress FE analysis on cargo tanks. In stress FE analysis, design loads usually include temperature distribution, design vapor pressure, and internal pressure caused by cargo during vessel acceleration. For temperature distribution among design loads, there are three loading conditions which are: cooling down, partial filling level, and full filling level loading conditions in an independent tank. Finally, FE results are to be used for assessing the yielding and buckling strength of a tank structure in terms of acceptance criteria. A case study for an LNG SPB tank demonstrates strength assessment considering thermal effects. The complete procedure has been developed for thermal analysis and strength evaluation of cargo tank structures in offshore FLNGs and LNG carriers.

scholarly journals Heat transfer analysis of insulation materials with flexible multilayers

2013 ◽  
Vol 17 (5) ◽  
pp. 1415-1420 ◽  
Author(s):  
Jin-Jing Chen ◽  
Zheng Guo ◽  
Wei-Dong Yu
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Temperature Distribution ◽  
Optimal Design ◽  
Heat Transfer Analysis ◽  
Harsh Environment ◽  
Transfer Model ◽  
Insulation Material ◽  
Study Heat Transfer ◽  
Harsh Conditions

A new flexible multilayer thermal insulation material is presented for applications at harsh environment as high as 433 K or as low as 123 K. A heat transfer model is established and solved to study heat transfer through the material, including radiation, solid heat transfer and gas heat transfer. Comparison between the experimental results and the theoretical prediction shows that the model is feasible to be applied in engineering. The temperature distribution of samples with 10, 15, 20, 25, 30 layers, respectively, the radiation, solid and gas heat transfer of a sample with 10 layers are analyzed at harsh conditions (123 K and 433 K) and the normal condition as well. The theoretical thermal analysis provides an active instruction to an optimal design of such protective materials.

Investigation Into Thermal Stress Characteristics of Pipe-in-Pipe Under High Temperature Condition

2018 ◽  
Author(s):  
Si-Hwa Jeong ◽  
Min-Gu Won ◽  
Nam-Su Huh ◽  
Yun-Jae Kim ◽  
Young-Jin Oh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
High Temperature ◽  
Temperature Distribution ◽  
Heat Transfer Analysis ◽  
Piping System ◽  
Curved Pipe ◽  
High Temperature Condition ◽  
Single Pipe ◽  
Radiation Conditions

In this paper, the thermal stress characteristics of the pipe-in-pipe (PIP) system under high temperature condition are analyzed. The PIP is a type of pipe applied in sodium-cooled faster reactor (SFR) and has a different geometry from a single pipe. In particular, under the high temperature condition of the SFR, the high thermal stress is generated due to the temperature gradient occurring between the inner pipe and outer pipe. To investigate the thermal stress characteristics, three cases are considered according to geometry of the support. The fully constrained support and intermediate support are considered for case 1 and 2, respectively. For case 3, both supports are applied to the actual curved pipe. The finite element (FE) analyses are performed in two steps for each case. Firstly, the heat transfer analysis is carried out considering the thermal conduction, convection and radiation conditions. From the heat transfer analysis, the temperature distribution results in the piping system are obtained. Secondly, the structural analysis is performed considering the temperature distribution results and boundary conditions. Finally, the effects of the geometric characteristics on the thermal stress in the PIP system are analyzed.

Thermal Analysis of Railroad Bearings: Effect of Wheel Heating

2009 ◽  
Author(s):  
Constantine M. Tarawneh ◽  
Arturo A. Fuentes ◽  
Brent M. Wilson ◽  
Kevin D. Cole ◽  
Lariza Navarro
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Roller Bearing ◽  
Railroad Wheel ◽  
Fe Model ◽  
Wheel Pair ◽  
Tapered Roller Bearing ◽  
Excessive Heat ◽  
Tapered Roller ◽  
Railroad Bearings

Catastrophic bearing failure is a major concern for the railroad industry because it can lead to costly train stoppages and even derailments. Excessive heat buildup within the bearing is one of the main factors that can warn of impending failure. A question is often raised regarding the transfer of heat from a wheel during braking and whether this can lead to false setouts. Therefore, this work was motivated by the need to understand and quantify the heat transfer paths to the tapered roller bearing within the railroad wheel assembly when wheel heating occurs. A series of experiments and finite element (FE) analyses were conducted in order to identify the different heat transfer mechanisms, with emphasis on radiation. The experimental setup consisted of a train axle with two wheels and bearings pressed onto their respective journals. One of the wheels was heated using an electric tape placed around the outside of the rim. A total of 32 thermocouples scattered throughout the heated wheel, the axle, and the bearing circumference measured the temperature distribution within the assembly. In order to quantify the heat radiated to the bearing, a second set of experiments was developed; these included, in addition to the axle and the wheel pair, a parabolic reflector that blocked body-to-body radiation to the bearing. The appropriate boundary conditions including ambient temperature, emissivity, and convection coefficient estimates were measured or calculated from the aforementioned experiments. The FE thermal analysis of the wheel assembly was performed using the ALGOR™ software. Experimental temperature data along the radius of the heated wheel, the bearing circumference, and at selected locations on the axle were compared to the results of the FE model to verify its accuracy. The results indicate that the effect of thermal radiation from a hot wheel on the cup temperature of the adjacent bearing is minimal when the wheel tread temperature is at 135°C (275°F), and does not exceed 17°C (31°F) when the wheel tread is at 315°C (600°F).

FE Analysis of Hot Strips’ Temperature Distribution in Laminar Cooling Process

2014 ◽  
Vol 900 ◽  
pp. 647-650
Author(s):  
Yu Qing Zheng ◽  
Jing Yu Cui
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Rolled Strip ◽  
Fe Model ◽  
Laminar Cooling ◽  
Cooling Process ◽  
Transfer Coefficients ◽  
Position Effects ◽  
Simulation Accuracy ◽  
Hot Rolled

The temperature distribution of the hot-rolled strip in the ROT cooling process was calculated and analyzed using ABAQUS in this paper. The complicated heat transfer coefficients of hot strip considering the position effects of top and bottom nozzles, and the non-uniform heat transfer situation along the width direction were defined by user subroutine. The simulation results were in good correlation with test results. It’s helpful for further analysis to improve the temperature distribution uniformity and the simulation accuracy for FE model, and guide the on-site production.

Analysis to Reduce Thermal Stress in Oxide Single Crystal During Czochralski Growth

2004 ◽  
Author(s):  
Shigeki Hirasawa ◽  
Hiroyuki Ishibashi ◽  
Kazuhisa Kurashige ◽  
Akihiro Gunji
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Temperature Distribution ◽  
Thermal Radiation ◽  
Single Crystal ◽  
Radiation Heat Transfer ◽  
Heat Transfer Analysis ◽  
Czochralski Growth ◽  
Radiation Heat ◽  
Radial Temperature

Temperature distributions and thermal stress distributions in a semi-transparent GSO crystal during Czochralski (CZ) single crystal growth were numerically investigated by thermal radiation heat transfer analysis and anisotropy stress analysis. As GSO has special optical properties, such as semi-transparency at a wavelength shorter than 4.5 μm, thermal radiation heat transfer was calculated by the Monte Carlo method. These calculations showed that thermal stress is caused by the radial temperature distribution on the outside of the upper part of the crystal. To reduce this temperature distribution, the following three manufacturing conditions were found to be effective: use a sharp taper angle of the crystal, install a lid to the top of the insulator, and install a ring around the tapered part of the crystal.

Numerical Assessment on Time-Varying Temperature Field of Bridge Tower under Solar Radiation

2012 ◽  
Vol 204-208 ◽  
pp. 2236-2239 ◽  
Author(s):  
Bo Chen ◽  
Wei Hua Guo ◽  
Chun Fang Song ◽  
Kai Kai Lu
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Solar Radiation ◽  
Ambient Air ◽  
Heat Transfer Analysis ◽  
Time Varying ◽  
Long Span ◽  
Bridge Tower

Bridge tower, time-varying temperature field, heat transfer analysis, finite element model. Abstract. Long span suspension bridges are subjected to daily, seasonal and yearly environmental thermal effects induced by solar radiation and ambient air temperature. This paper aims to investigate the temperature distribution of a tower of a long span suspension bridge. Two-dimensional heat transfer models are utilized to determine the time-dependent temperature distribution of the bridge tower of the bridge. The solar radiation model is utilized to examine the time-varying temperature distribution. Finite element models are constructed for the bridge tower to compute the temperature distribution. The numerical models can successfully predict the structural temperature field at different time. The methodology employed in the paper can be applied to other long-span bridges as well.

scholarly journals Theoretical Evaluation of Microwave Ablation Applied on Muscle, Fat and Bone: A Numerical Study

2021 ◽  
Vol 11 (17) ◽  
pp. 8271 ◽  
Author(s):  
Cheng Chen ◽  
Ming-An Yu ◽  
Lin Qiu ◽  
Hong-Yu Chen ◽  
Zhen-Long Zhao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Biological Tissue ◽  
Microwave Ablation ◽  
Numerical Study ◽  
Biological Tissues ◽  
Heat Transfer Analysis ◽  
Temperature Threshold ◽  
Radiation Physics ◽  
Experimental Conditions

(1) Background: Microwave ablation (MWA) is a common tumor ablation surgery. Because of the high temperature of the ablation antenna, it is strongly destructive to surrounding vital tissues, resulting in high professional requirements for clinicians. The method used to carry out temperature observation and damage prediction in MWA is significant; (2) Methods: This work employs numerical study to explore temperature distribution of typical tissues in MWA. Firstly, clinical MWA based on isolated biological tissue is implemented. Then, the Pennes models and microwave radiation physics are established based on experimental parameters and existing related research. Initial values and boundary conditions are adjusted to better meet the real clinical materials and experimental conditions. Finally, clinical MWA data test this model. On the premise that the model is matched with clinical MWA, fat and bone are deduced for further heat transfer analysis. (3) Results: Numerical study obtains the temperature distribution of biological tissue in MWA. It observes the heat transfer law of ablation antenna in biological tissue. Additionally, combined with temperature threshold, it generates thermal damage of biological tissues and predicts the possible risks in MWA; (4) Conclusions: This work proposes a numerical study of typical biological tissues. It provides a new theoretical basis for clinically thermal ablation surgery.

scholarly journals Two-dimensional heat transfer analysis of timber structure walls filled with hemp-lime composite

2019 ◽  
Vol 252 ◽  
pp. 05015 ◽  
Author(s):  
Przemysław Brzyski ◽  
Sylwia Duda ◽  
Andrzej Raczkowski
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Timber Structure ◽  
Heat Transfer Analysis ◽  
Two Dimensional ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Thermal Insulating ◽  
Frame Construction ◽  
Industrial Hemp

Hemp-lime composite is a thermal insulating material used as a filling in timber frame construction walls. It is a material based on the wooden part of industrial hemp stalk (hemp shives) and lime binder. In practice, different wall thicknesses, composites with different thermal properties and various configurations of timber structure are used. These factors affect the temperature distribution in the wall. In the thermally weaker areas of walls, there is a greater risk of condensation and mould growth. This issue is important while designing walls based on organic materials. The paper presents the two-dimensional (2D) heat-transfer analysis based on the finite-element method, using THERM software. Several variants of external walls were adopted for the analysis. Thermal parameters of hemp-lime composites used in the analysis were obtained from our own research. The results of the analysis were presented as the values of the thermal transmittance coefficient and linear thermal transmittance equivalent to timber construction. The temperature distribution for an exemplary wall was also shown graphically in the form of isotherms and colour-flooded isotherms.

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