A Model for Predicting the Temperature Distribution Around Radioactive Waste Containers in Very Deep Geological Boreholes

2008 ◽  
Vol 1107 ◽  
Author(s):  
Karl P. Travis ◽  
Neil A. McTaggart ◽  
Fergus G. F. Gibb ◽  
David Burley
Keyword(s):  
Mathematical Model ◽  
Temperature Field ◽  
High Temperature ◽  
Temperature Distribution ◽  
Low Temperature ◽  
Radioactive Waste ◽  
Temperature Rise ◽  
Deep Borehole ◽  
Numerical Work

AbstractWe present a mathematical model for determining the temperature field around radioactive waste containers in very deep geological boreholes. The model is first used to predict the temperature rise for some simple, but well-established cases with known solutions in order to verify the numerical work. The temperature distribution is then determined for two variants of the deep bore hole concept; a low temperature variant and a high temperature variant. The results from these studies are discussed in terms of their utility in establishing deep borehole disposal as a workable concept.

Research of the Temperature Field Distribution Based on FVM for Oil-Immersed Transformer

2014 ◽  
Vol 1079-1080 ◽  
pp. 510-514
Author(s):  
Yong Qiang Wang ◽  
Jie He ◽  
Lun Ma ◽  
Liu Wang ◽  
Ying Ying Sun ◽  
...  
Keyword(s):  
Temperature Field ◽  
High Temperature ◽  
Temperature Distribution ◽  
Field Distribution ◽  
Hot Spot ◽  
Load Capacity ◽  
Normal Operation ◽  
Internal Temperature ◽  
Temperature Field Distribution ◽  
Spot Temperature

Thehottest spot temperature (HST) of windings of oil-immersed transformer is animportant factor that affects load capacity and operation life of transformer,and is closely related to the transformer load, top oil and environmenttemperature. HST, when operating at high temperature and overload, may lead totransformer failure which will affect the normal operation of the power system.In order to calculate the transformer hot spot temperature accurately, we takea 33MVA-500KV transformer as an example, and establish a three dimensionalmodel, get its internal temperature distribution based on Fluent simulationsoftware. At last, we comparative and analysis the accuracy of FVM calculation andIEEE guidelines recommend model combined with online monitored values. Theresults show that the FVM method with higher accuracy relative to the IEEEguidelines model, proved that using the FVM can accurately calculate the HST ofoil-immersed transformer.

scholarly journals Mathematical model of heat transfer in roll caliber

2019 ◽  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Boundary Value Problem ◽  
Boundary Conditions ◽  
Heat Equation ◽  
Rolling Mill ◽  
Thermal Process ◽  
Stationary Heat

A physical model of the thermal process in the roll caliber during the rolling of the tape on a two-roll rolling mill was constructed. A mathematical model of the temperature field of a rolling hollow roll of a rolling state of a cylindrical shape rotating about its axis with constant angular velocity is proposed. The mathematical model takes into account different conditions of heat exchange of the inner and outer surfaces of the roll with the belt and its surrounding environment. The temperature field of a hollow roll of a rolling mill is considered as an initial boundary-value problem for a homogeneous non-stationary heat equation with inhomogeneous, nonlinear boundary conditions, which also depend on the angle of rotation of the roll around its axis. The equation describes the temperature field of the rolls during uncontrolled heat transfer during rolling. It significantly depends on the time and number of revolutions around its axis. With a large number of revolutions of the roll around its axis, a quasi-stationary temperature distribution occurs. Therefore, the simplified problem of determining a quasistationary temperature field, which is associated with a thermal process that is time-independent, is considered further in the work. In this case, the temperature field is described using the boundary value problem in a ring for a homogeneous stationary heat equation with inhomogeneous boundary conditions and heat transfer conditions outside the ring, which lie from the angular coordinate. After the averaging operation, the solution of this problem is reduced to solving the equivalent integral equation of Hammerstein type with a kernel in the form of the Green's function. The Mathcad computer mathematical system builds the temperature distribution of the roll surface. An algorithm for solving a inhomogeneous problem was developed and the temperature distribution of the roll was constructed.

Thermal Considerations in a Very Deep Borehole Nuclear Waste Repository for Synroc

2000 ◽  
Vol 663 ◽  
Author(s):  
G.D. Sizgek
Keyword(s):  
Temperature Field ◽  
Radioactive Waste ◽  
High Level Waste ◽  
Nuclear Waste Repository ◽  
Heat Output ◽  
Deep Borehole ◽  
Surface Cooling ◽  
Cooling Period ◽  
Waste Repository ◽  
High Level

ABSTRACTA study of heat propagation in a very deep borehole radioactive waste repository for Synroc is presented. The deep borehole modeled for the high level wastes is hypothetically sited at approximately 4 km below ground level in a granite host rock. The high level waste containers are placed in the lower section of the borehole to within 1.5 km of the surface and backfilled. A geothermal gradient of 0.03°C/m is assumed. Transient temperature field calculations are carried out for both 20 wt% and 10 wt% high level radioactive waste (HLW) bearing Synroc, for cooling periods between reactor discharge and geological disposal varying from 5 years to 50 years. The temperatures in the borehole repository were found to be very sensitive to the surface cooling period as well as the waste loading. The initial heat input of the waste may be controlled by cooling in an interim storage until the total heat output is reduced to a suitably low level. Therefore, surface cooling of at least 15 years for 20 wt% HLW containing Synroc is necessary for the given deep bore hole configuration to avoid the centerline temperatures that might affect durability of Synroc if ground water obtained access to the waste form. On the other hand the corresponding minimum surface cooling period for 10 wt% HLW containing Synroc is predicted to be about 5 years to produce similar temperature profiles in the borehole to those of 20 wt% HLW bearing Synroc with a 15-year cooling period before disposal. A variation in the borehole diameter has also been performed to elucidate the sensitivity of the temperature field of the repository.

A Fast and Low Temperature Eco-Process for Alloy's Joining

2006 ◽  
Vol 510-511 ◽  
pp. 886-889
Author(s):  
Zheng Yi Fu ◽  
D.H. He ◽  
Jing Ying Zhang ◽  
Wei Min Wang ◽  
Hang Wang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Temperature Distribution ◽  
Low Temperature ◽  
Holding Time ◽  
Lower Pressure ◽  
Heat Diffusion ◽  
High Tensile Strength ◽  
Joining Process

In this paper, we suggest PCH as a method of joining alloys. The temperature distribution in the samples during the joining process was analyzied. From the temperature distribution profiles in PCH joining, it is concluded that PCH for the joining has two advantages: (1) There is a temperature distribution peak along the sample. The contacting surfaces which need high temperature happen to obtain the highest temperature; (2) The parts to be joined at relatively lower temperatures can avoid the damage of heat attack. The optimal joining conditions were discussed. The PCH and HP techniques were compared for the joining of alloys. It was found that the high tensile strength joined structure of alloys can be fabricated by PCH method at lower joining temperature, shorter holding time, and lower pressure, compared with that by HP method. The PCH process was considered to be an eco-friendly process compared with the traditional heat diffusion joining methods.

Study on Mathematical Model of Temperature Field in the Laser Welding Process

2010 ◽  
Vol 426-427 ◽  
pp. 89-92
Author(s):  
Hong Feng Wang ◽  
Dun Wen Zuo ◽  
Ming Min Huang ◽  
Hong Miao
Keyword(s):  
Mathematical Model ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Source ◽  
Laser Welding ◽  
Welding Process ◽  
Actual Process ◽  
Analytical Results ◽  
The Mathematical Model ◽  
Laser Welding Process

From the laser welding actual process, the welding heat source model of laser welding process was established, that is, superposition heat source. According to the knowledge of thermodynamics, the establishment of a welding process, the mathematical model of temperature distribution of laser welding process was obtained by laser welding heat source. Finally, the finite element simulation of welding temperature distribution was used. The simulated results were compared with the analytical results of mathematical model of temperature field, it was proved consistent between simulated results and analytical results, at the same time it can account for the correctness of the mathematical model of temperature field.

Temperature rise characteristic of MR fluid in a multi-disc MR clutch under slip condition

2015 ◽  
Vol 67 (2) ◽  
pp. 85-92 ◽  
Author(s):  
Daoming Wang ◽  
Youfu Hou ◽  
Zuzhi Tian ◽  
Qingrui Meng
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Temperature Rise ◽  
Slip Condition ◽  
Impact Factors ◽  
Gap Size ◽  
Mr Fluid ◽  
Content Type ◽  
Heat Transfer Theory ◽  
The Impact

Purpose – This study aims to reveal the temperature rise characteristic of magnetorheological (MR) fluid in a multi-disc MR clutch under slip condition, including the temperature distribution regularity and the impact factors. Design/methodology/approach – Three-dimensional transient heat conduction equation for the MR fluid in the working gap was derived based on the heat transfer theory. Then, numerical simulation was conducted to analyze the temperature field of MR fluid. Furthermore, an experimental study was performed to explore the temperature distribution of the MR fluid in radial and circumferential directions, as well as the effects of disc groove, slip power and gap size on temperature rise characteristic of the MR fluid. Findings – The results show that temperature appears to be largest in the center of the working gap and the temperature difference increases with the slip time. However, the temperature field in a circumferential direction is basically the same, but it presents slightly lower in the groove area. The temperature of the MR fluid increases linearly with the slip time and the rise rate increases with the slip power. Moreover, the temperature rise value decreases with the increase of gap size. Originality/value – In this paper, the temperature gradients, both in radial and circumferential directions, are experimentally measured going beyond the estimation by computer simulations. In addition, the factors that influence the temperature rise characteristic of MR fluid were fully analyzed. The results could provide a reliable basis for the development of cooling technology for high-power MR devices.

scholarly journals Temperature Non-Homogeneieties in a Catalytic Reactor With a Periodic Change in the Direction of the Reaction Mixture Feed

2015 ◽  
Vol 45 (2) ◽  
pp. 75-90
Author(s):  
Ivanka Zheleva
Keyword(s):  
High Temperature ◽  
Temperature Distribution ◽  
Low Temperature ◽  
Catalyst Layer ◽  
Middle Part ◽  
Periodic Change ◽  
Reactor Wall ◽  
High Porosity ◽  
Catalytic Reactor ◽  
Wall Area

AbstractTemperature non-homogeneities in a catalytic reactor with periodic change in the direction of the reaction mixture feed is investigated in the present work. The temperature of the reaction mixture is described using a numerical algorithm for simulation of the work of the catalytic reactor, graphically shown and commented. The influence of the higher catalyst layer porosity in the wall area upon the temperature distribution in the reactor is studied. The existence of two different regimes is shown - a high temperature one in the middle part of the layer and a low temperature one in the high porosity area of the layer in contact with the reactor wall. This leads to not very effective usage of the catalyst in these parts of the catalyst layer in the reactor. This simulation can be used for better understanding and controlling of the examined catalytic process.

The Temperature Distribution Analysis of the Large LNG-FSRU

2016 ◽  
Author(s):  
Chong Wang ◽  
Hongde Qin ◽  
Jing Shen ◽  
Xiuzi Hao
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Low Temperature ◽  
Temperature Difference ◽  
Heat Transfer Process ◽  
Large Temperature ◽  
Distribution Analysis ◽  
Double Row ◽  
Hull Structure ◽  
The Mathematical Model

LNG-FSRU (Liquefied Natural Gas-Floating Storage and Regasification Unit) can adopt the structure of double-row cargo tanks. Meanwhile, its heat maintenance system has the characteristics of the special structure, the large temperature difference between inside and outside and the complicated heat transfer process. Aiming at this particular structural form and considering the hull structure and some effect of convection in cavity, this paper establishes the mathematical model and utilizes the finite element method to conduct the deep analysis of ultra-low temperature field in order to obtain its temperature distribution in the ultra-low temperature field. Moreover, the results indicate that the temperature distribution of the double-row-tank structure is linear from the inside out with the relatively uniform overall distribution; the temperature difference above and below the waterline has affects the temperature distribution of the inner shells; the temperature of the middle longitudinal cofferdam zone is relatively lower than that of other areas.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

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