Utilization of Elastic Deformation on Cu–Ag Nanoscale Particles Mixed in Hydrogen Oxide with Unique Features of Heat Generation/Absorption: Closed Form Outcomes

2019 ◽  
Vol 44 (6) ◽  
pp. 5949-5960 ◽  
Author(s):  
Bilal Ahmad ◽  
Z. Iqbal ◽  
E. N. Maraj ◽  
S. Ijaz
Keyword(s):  
Closed Form ◽  
Elastic Deformation ◽  
Heat Generation ◽  
Nanoscale Particles ◽  
Hydrogen Oxide

Friction Heat Due to Sliding of Rough Surfaces: Micro-Scale Interactions and Their Macro-Scale Effect

2008 ◽  
Author(s):  
K. Farhang ◽  
A. Elhomani
Keyword(s):  
Closed Form ◽  
Heat Generation ◽  
Rough Surfaces ◽  
Integral Form ◽  
Sliding Contact ◽  
Heat Generation Rate ◽  
Friction Heat ◽  
Single Asperity ◽  
Macro Scale ◽  
Statistical Integral

When two rough surfaces are in sliding contact an asperity on a surface would experience intermittent temperature flashes as it comes in momentary contact with asperities on a second surface. The frequency of the flash temperatures, their strength and duration depend, in addition to the sliding speed, on the topology of the two surfaces. In this paper a model is developed for the work-heat relation with a consideration of the above-mentioned intermittent nature of contact. The work of friction on one asperity is derived in integral form and closed-form equations. The rate of generation of heat is found due to a single asperity. Using the statistical account of asperity friction heat generation, rate of heat generation between two rough surfaces is obtained both in statistical integral form and in the approximate closed form.

Closed Form Solutions For Mixed Convection With Magnetohydrodynamic Effect in a Vertical Porous Annulus Surrounding an Electric Cable

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
A. Barletta ◽  
E. Magyari ◽  
S. Lazzari ◽  
I. Pop
Keyword(s):  
Mixed Convection ◽  
Closed Form ◽  
Heat Generation ◽  
Internal Heat ◽  
Boussinesq Approximation ◽  
Closed Form Solutions ◽  
Electric Cable ◽  
Special Cases ◽  
Magnetohydrodynamic Effect ◽  
The Magnetic Field

Mixed convection Darcy flow in a vertical porous annulus around a straight electric cable is investigated. It is assumed that the flow is fully developed and parallel. Moreover, the Boussinesq approximation is used. The magnetic field with a steady electric current in the cable is radially varying according to the Biot–Savart law. Two flow regimes are investigated. The first is mixed convection with negligible effects of internal heat generation due to Joule heating and viscous dissipation. The second is forced convection with important effects of heat generation. In these two special cases, closed form expressions of the velocity profile and of the temperature profile, as well as of the flow rate and the Nusselt number, are obtained. The main features of these solutions are discussed.

Optimum Profile of Thin Fins With Volumetric Heat Generation: A Unified Approach

2005 ◽  
Vol 127 (8) ◽  
pp. 945-948 ◽  
Author(s):  
B. Kundu ◽  
P. K. Das
Keyword(s):  
Closed Form ◽  
Heat Generation ◽  
Variational Calculus ◽  
Optimality Criteria ◽  
Closed Form Expression ◽  
Pin Fins ◽  
Fin Thickness ◽  
Optimum Profile ◽  
Special Case ◽  
Volumetric Heat Generation

In this paper, a generalized methodology for the optimum design of thin fins with uniform volumetric heat generation is described. Using variational calculus, the optimum profiles of longitudinal, annular, and pin fins are determined from the basic fin equation under the constraint of specified fin volume. From a common optimality criteria, a generalized closed form expression for the fin thickness is obtained for the above three types of fins. Closed-form expressions are also obtained for the optimum profiles of longitudinal and pin fins. As a special case, both the temperature profile and the shape of optimum fins without heat generation are determined.

scholarly journals Performance of Tilting Pad Journal Bearings with the Same Sommerfeld Number

2020 ◽  
Vol 10 (10) ◽  
pp. 3529
Author(s):  
Sung-Hwa Jeung ◽  
Junho Suh ◽  
Hyun Sik Yoon
Keyword(s):  
Thermal Behavior ◽  
Elastic Deformation ◽  
Heat Generation ◽  
Thermal Deformation ◽  
Journal Bearings ◽  
Hertzian Contact ◽  
Maximum Temperature ◽  
Oil Film ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearings

This paper presents the change of non-dimensional characteristics and thermal behavior of different sized tilting pad journal bearings (TPJBs) with the same Sommerfeld number. A three-dimensional (3D) TPJB numerical model is provided considering the thermo-elastic hydro-dynamic (TEHD) lubrication model with pad thermal-elastic deformation. The pivot stiffness is assumed to be the combination of linear and cubic stiffness based on the Hertzian contact theory. The TPJBs in a configuration of load between pad (LBP) with the same Sommerfeld number having seven different sizes are simulated, and their non-dimensional dynamic and static characteristics and thermal behavior are compared. Pad thermal and elastic deformation are both taken into account. If the changes in lubricant viscosity, thermal deformation, and elastic deformation of journal/pads due to viscous shearing are ignored, the bearings with identical Sommerfeld numbers should show the same performance characteristics. However, the heat generation at the bearing clearance during operation (a) induces a decrease in viscosity and heat transfer to journal/pads and (b) results in a thermal deformation. Furthermore, the elastic deformation of the tilting pads and pivots also affects the bearing dynamic performance. For the same Sommerfeld number, the numerical analyses provide how the viscous shearing and elastic deformation lead to a change in bearing performance. For the small bearings with the same Sommerfeld number, the non-dimensional characteristics did not change significantly, where the heat generation was small being compared to the large sized bearing. The largest change in non-dimensional characteristics occurred when the maximum temperature of the oil film increased by 30 °C or more compared to the lubricant supply temperature. The root cause of the change in the non-dimensional characteristics is the viscous shearing in the oil film, and the thermal deformation of the structures surrounding the oil film acts in combination. These results provide insight into the Sommerfeld number, which can be used for the early stage of bearing design.

Design of a Compliant Hinge Based on Closed Form Pressure Balancing

2020 ◽  
Author(s):  
Robin F. P. Gomes ◽  
Joep P. A. Nijssen ◽  
Ron A. J. van Ostayen
Keyword(s):  
Closed Form ◽  
Elastic Deformation ◽  
Compliant Mechanisms ◽  
State Of The Art ◽  
3D Analysis ◽  
Stiffness Ratio ◽  
Rotational Stiffness ◽  
Fluid Medium ◽  
Form Pressure ◽  
Rotation Stiffness

Abstract Compliant mechanisms consist of a monolithic body and obtain motion through elastic deformation. Multiple compliant flexure designs are known but their translational to rotation stiffness ratio is often limited. This work introduces a novel compliant hinge design with increased stiffness ratio compared to the state of the art compliant hinges. The hinge functions by having an encapsulated fluid medium that contributes to high normal stiffness, but doesn’t influence the rotational stiffness. A 2D design model is presented that shows the effect of the geometry on the stiffness ratio performance. Subsequently, a computational 3D analysis is performed and the resulting design is realized as a demonstrator. The performance is compared to conventional compliant hinges based on the stiffness ratio. This shows an increase of at least a factor 30 on the stiffness ratio.

Closed-Form Analysis for Elastic Deformations of Multilayered Strands

1987 ◽  
Vol 54 (4) ◽  
pp. 898-903 ◽  
Author(s):  
K. Kumar ◽  
J. E. Cochran
Keyword(s):  
Closed Form ◽  
Elastic Deformation ◽  
Design Criterion ◽  
Deformation Characteristics ◽  
Simple Design ◽  
Elastic Deformations ◽  
Form Analysis ◽  
Closed Form Solutions ◽  
Analytical Results ◽  
Torsional Loads

Closed-form solutions are developed for elastic deformation characteristics of multilayered strands under tensile and torsional loads. These analytical results are successfully applied to obtain expressions for the effective extensional and torsional moduli of rigidity for the strands. Finally, a simple design criterion is established for “nonrotating” cables.

A Statistical Account of Asperity Heating in a Rough Surface Contact

2007 ◽  
Author(s):  
K. Farhang ◽  
A. Elhomani
Keyword(s):  
Closed Form ◽  
Heat Generation ◽  
Rough Surfaces ◽  
Integral Form ◽  
Sliding Contact ◽  
Heat Generation Rate ◽  
Friction Heat ◽  
Single Asperity ◽  
Rough Surface Contact ◽  
Statistical Integral

When two rough surfaces are in sliding contact an asperity on a surface would experience intermittent temperature flashes as it comes in momentary contact with asperities on a second surface. The frequency of the flash temperatures, their strength and duration depend, in addition to the sliding speed, on the topology of the two surfaces. In this paper a model is developed for the work-heat relation with a consideration of the above-mentioned intermittent nature of contact. The work of friction on one asperity is derived in integral form and closed-form equations. The rate of generation of heat is found due to a single asperity. Using the statistical account of asperity friction heat generation, rate of heat generation between two rough surfaces is obtained both in statistical integral form and in the approximate closed form.

Heat Generation and Transport in the Earth

2010 ◽  
Author(s):  
Claude Jaupart ◽  
Jean-Claude Mareschal
Keyword(s):  
Heat Generation ◽  
The Earth
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