Transient Temperature Distributions and Thermal Stresses in a Skin-Shear Web Configuration at High-Speed Flight for a Wide Range of Parameters

1955 ◽  
Vol 22 (12) ◽  
pp. 829-836 ◽  
Author(s):  
H. SCHUH
Keyword(s):  
High Speed ◽  
Thermal Stresses ◽  
Transient Temperature ◽  
Temperature Distributions ◽  
Wide Range

The Transient Temperature Distribution in a Slab Subject to Thermal Radiation

1965 ◽  
Vol 87 (1) ◽  
pp. 117-130 ◽  
Author(s):  
R. D. Zerkle ◽  
J. Edward Sunderland
Keyword(s):  
Temperature Distribution ◽  
Thermal Radiation ◽  
Radiant Heat ◽  
Analog Computer ◽  
Graphical Form ◽  
Transient Temperature ◽  
Transient Temperature Distribution ◽  
Temperature Distributions ◽  
Approximate Analytical Solutions ◽  
Wide Range

The transient, one-dimensional temperature distribution is determined for a slab, insulated on one face, and subjected to thermal radiation at the other face. The slab is initially at a uniform temperature and is assumed to be homogeneous, isotropic, and opaque; the physical properties are assumed to be independent of temperature. Transient temperature distributions for both heating and cooling situations are obtained by means of a thermal-electrical analog computer. A diode limiter circuit is used to simulate the nonlinear radiant heat flux. The transient temperature distributions are presented in a dimensionless, graphical form for a wide range of variables. Approximate analytical solutions are also given which complement and extend the solution charts over ranges of parameters not covered in the charts.

Aerodynamic Heating Numerical Simulation of Terminal-Sensitive Projectile at Deceleration and Despinning Trajectory

2013 ◽  
Vol 376 ◽  
pp. 317-322
Author(s):  
Jun Zhang ◽  
Rong Zhong Liu ◽  
Rui Guo ◽  
Xiao Dong Ma
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Thermal Protection ◽  
Thermal Characteristics ◽  
Simulation Method ◽  
Aerodynamic Heating ◽  
Transient Temperature ◽  
Physical Parameters ◽  
Temperature Distributions ◽  
Infrared Signature

Aero-heating problem severely affects the performance of terminal-sensitive projectile (TSP) when projected out of the carrier capsule by the gunpowder gas at a high speed. In this paper, based on the typical ballistic data and airflow physical parameters at deceleration and despinning trajectory, the aerodynamic thermal characteristics of a TSP was simulated by Fluent, and the transient temperature distributions were obtained under the different flying conditions. Finally, we got stagnation temperatures by the numerical simulations which were similar to those by the engineering evaluation, and demonstrate the effectiveness of the simulation method. The results are valuable to the research of thermal protection and infrared signature of TSP.

Transient Temperature Distributions and Thermal Stresses in Fuselage Shells with Bulkheads or Frames

1956 ◽  
Vol 60 (552) ◽  
pp. 799-804 ◽  
Author(s):  
J. S. Przemieniecki
Keyword(s):  
Temperature Distribution ◽  
Time Variation ◽  
Heat Input ◽  
Thermal Stresses ◽  
Aerodynamic Heating ◽  
Transient Temperature ◽  
Light Alloy ◽  
Temperature Distributions ◽  
Set Up ◽  
Fuselage Skin

SummaryThe temperature distribution and thermal stresses are calculated in a configuration consisting of a cylindrical fuselage shell with bulkheads or frames. It is shown that at supersonic speeds thermal stresses are set up in a conventional fuselage structure as a result of the bulkhead restraint against circumferential expansion of the fuselage skin. The thermal stresses due to restraint by fuselage frames are usually less severe. The relative merits of various combinations of materials for the skin and the bulkhead diaphragm are discussed. Furthermore, the possibility of the use of light alloy bulkheads to alleviate thermal stresses is investigated. Diagrams are given for calculating maximum thermal stresses and stress-time variation for various rates of heat input in the fuselage skin due to aerodynamic heating.

Experimental Investigation On Wear Behavior of Rectangular Labyrinth Fin Against High Speed Rotor

2021 ◽  
Author(s):  
Xin Yan ◽  
Xinbo Dai
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Wear Behavior ◽  
Early Stage ◽  
Labyrinth Seal ◽  
Contact Forces ◽  
Transient Temperature ◽  
Sliding Velocity ◽  
Material Loss ◽  
Temperature Distributions

Abstract The wear behaviors of a rectangular labyrinth seal fin against high speed rotor were experimentally investigated on the incursion test rig. The material losses, worn geometries, frictional temperature distributions, and contact forces of labyrinth fin in rubbing events were measured at three incursion rates, three final incursion depths and two rotor sliding velocities. The morphologies of the worn labyrinth fin tips were magnified to reveal the wear mechanisms in rubbing events. The transient temperatures and contact forces were detailed to analyze the thermal-mechanical interactions between two contacting parts. The results show that the material loss percentage in the labyrinth fin is higher at the early stage of rubbing process, accounting for 18% mass loss of the worn region, than at final stage. The material loss is decreased with increasing the incursion rate. The incursion rate and final incursion depth have pronounced effects on the mushroom region extensions and curlings. The friction coefficient is fluctuated significantly in the high sliding velocity and low incursion rate conditions, and the averaged value of friction coefficient is about 0.1-0.125 among all experiments. The temperature at labyrinth fin tip is increased with increasing the final incursion depth, incursion rate and sliding velocity. However, the temperature at fin tip is not increased further as it reaches about 1200°C. The heat convection from hot fin to ambient plays an important role in worn geometries and transient temperature distributions at fin tip.

Multizone Porous Medium Model of Thermal/Fluid Processes During Discharge of an Inclined Rectangular Storage Vessel Via an Immersed Heat Exchanger

2007 ◽  
Vol 129 (4) ◽  
pp. 449-457 ◽  
Author(s):  
Yan Su ◽  
Jane H. Davidson
Keyword(s):  
Porous Medium ◽  
Heat Exchanger ◽  
Storage Tank ◽  
Transient Temperature ◽  
Width Ratio ◽  
Dimensional Model ◽  
Temperature Distributions ◽  
Wide Range ◽  
Convective Thermal ◽  
Porous Medium Model

The transient natural convective thermal/fluid processes during discharge of an inclined rectangular solar storage tank via an immersed heat exchanger are modeled and compared to prior experimental data. The model treats the heat exchanger as a porous medium within the storage fluid and is applicable to a wide range of tank/heat exchanger configurations. In the present study, a two-dimensional model is applied to discharge of a 126l storage tank inclined at 30deg with respect to the horizontal and with a height to width ratio of 9:1. The heat exchanger has 240 tubes arranged in parallel and is located near the top of the tank. Transient temperature distributions and flow streamlines demonstrate the complexity of the flow field and the extent of mixing during discharge. The predicted results compare favorably to prior measurements of heat transfer and temperature distribution.

CFD Analysis of Thermally Stratified Flow and Conjugate Heat Transfer in a PWR Pressurizer Surgeline

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Jong Chull Jo ◽  
Dong Gu Kang
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Thermal Stresses ◽  
Complex Geometry ◽  
Heat Removal ◽  
Heat Transfer Analysis ◽  
Transient Temperature ◽  
Piping System ◽  
Pressurized Water ◽  
Temperature Distributions

Temperature gradients in the thermally stratified fluid flowing through a pipe may cause undesirable excessive thermal stresses at the pipe wall in the axial, circumferential, and radial directions, which can eventually lead to damages such as deformation, support failure, thermal fatigue, cracking, etc., to the piping systems. Several nuclear power plants have so far experienced such unwelcome mechanical damages to the pressurizer surgeline, feedwater nozzle, high pressure safety injection lines, or residual heat removal lines at a pressurized water reactor (PWR). In this regard, determining with accuracy the transient temperature distributions in the wall of a piping system subjected to internally thermal stratification is the essential prerequisite for the assessment of the structural integrity of such a piping system. In this study, to realistically predict the transient temperature distributions in the wall of an actual PWR pressurizer surgeline with a complex geometry of three-dimensionally bent piping, three-dimensional transient computational fluid dynamics (CFD) calculations involving the conjugate heat transfer analysis are performed for the PWR pressurizer surgeline subjected to either out- or in-surge flows using a commercial CFD code. In addition, the wall temperature distributions obtained by taking into account the existence of wall thickness are compared with those by neglecting it to identify some requirements for a realistic and conservative thermal analysis from a safety viewpoint.

Multipass Serpentine Cooling Designs for Negating Coriolis Force Effect on Heat Transfer: 45-deg Angled Rib Turbulated Channels

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Prashant Singh ◽  
Yongbin Ji ◽  
Srinath V. Ekkad
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Thermal Stresses ◽  
Suction Side ◽  
Reynolds Numbers ◽  
Liquid Crystal Thermography ◽  
Wide Range ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Stationary Conditions

Rotation-induced Coriolis and centrifugal buoyancy forces result in significant modification of cooling characteristics of blade pressure and suction side internal walls. The nonuniformity in cooling, coupled with high-speed rotation, results in increased levels of thermal stresses. To address this problem, this study presents two multipassage configurations featuring 45-deg angled turbulators, in four- and six-passage designs. Experiments were carried out under stationary and rotating conditions using transient liquid crystal thermography to measure detailed heat transfer coefficient. It has been shown through experimental data that heat transfer characteristics of the new configurations’ pressure and suction side internal walls were very similar under rotating conditions, at both local and global scales. The heat transfer levels under rotating conditions were also similar to those of the stationary conditions. The contribution of multiple passages connected with 180-deg bends toward overall frictional losses has been evaluated in terms of pumping power and normalized friction factor. The configurations are ranked based on their thermal hydraulic performances over a wide range of Reynolds numbers. The four-passage ribbed configuration had slightly higher heat transfer levels compared with those of the corresponding six-passage ribbed configuration.

Correlation of Theoretical and Photothermoelastic Results on Thermal Stresses in Idealized Wing Structures

1960 ◽  
Vol 27 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Herbert Tramposch ◽  
George Gerard
Keyword(s):  
Thermal Stress ◽  
Thermal Behavior ◽  
Experimental Evaluation ◽  
High Speed ◽  
Thermal Stresses ◽  
Initial Conditions ◽  
Temperature Distributions ◽  
Wing Structures ◽  
Simplifying Assumptions ◽  
Transient Thermal

After a rather complete exploratory program described in previous papers, the photothermoelastic method was applied to the experimental evaluation of thermal-stress theories. The new technique was correlated with several theories which analyzed the transient thermal stresses in idealized wing structures of high-speed aircraft. Various theories were investigated which represented the same idealized wing models and differed from each other only in the simplifying assumptions regarding the temperature distributions in skin and webs. The theories were evaluated by duplicating the boundary and initial conditions on plastic models and then by correlating the theories with the observed fringe orders in nondimensional form. A significant general conclusion was reached after correlating the available theories and experimental results. Owing to simplifying assumptions concerning the thermal behavior in the flanges, thermal stresses predicted by the available theories are all higher than the experimental observation. In some cases the discrepancy is as great as 30 per cent.

CFD Analysis of Thermally Stratified Flow and Heat Transfer in a PWR Pressurizer Surge Line

2008 ◽  
Author(s):  
Dong Gu Kang ◽  
Jong Chull Jo
Keyword(s):  
Heat Transfer ◽  
Wall Thickness ◽  
Thermal Stratification ◽  
Thermal Stresses ◽  
Complex Geometry ◽  
Heat Transfer Analysis ◽  
Transient Temperature ◽  
Piping System ◽  
Temperature Distributions ◽  
Surge Line

Temperature gradients in the thermally stratified fluid flowing through a pipe may cause undesirable excessive thermal stresses at the pipe wall in the axial, circumferential, and radial directions, which can eventually lead to damages such as deformation, support failure, thermal fatigue, cracking, etc. to the piping systems. Several nuclear power plants have so far experienced such unwelcome mechanical damages to the pressurizer surge lines, feedwater nozzle, high pressure safety injection lines, or residual heat removal lines. In this regard, to determine the transient temperature distributions in the wall of a piping system subjected to internally thermal stratification with accuracy is the essential prerequisite for the assessment of the structural integrity of the piping system subjected to internally thermal stratification. In this study, to predict the transient temperature distributions in the wall of PWR pressurizer surge line with a complex geometry of 3-dimensionally bent piping realistically, 3-dimensional transient CFD calculations involving the conjugate heat transfer analysis are performed for the actual PWR pressurizer surge line subjected to stratified internal flows either during out-surge or in-surge operation using a commercial CFD code. In addition, the wall temperature distributions obtained by taking account of the existence of wall thickness as it is are compared with those by neglecting the existence of wall thickness to identify some requirements for a realistic and conservative thermal analysis.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

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