Effect of rigidities on the profiles of the optimum temperature fields in the local heating of orthotropic cylindrical shells

1974 ◽  
Vol 7 (5) ◽  
pp. 544-546
Author(s):  
B. L. Pelekh ◽  
I. G. Sirenko
Keyword(s):  
Local Heating ◽  
Cylindrical Shells ◽  
Temperature Fields ◽  
Optimum Temperature

Numerical Investigations on Bearing Capacity of Grid-Stiffened Cylindrical Shells Subjected to Local Laser Irradiation

2013 ◽  
Vol 444-445 ◽  
pp. 72-76
Author(s):  
Hai Hong Liu ◽  
Lian Chun Long
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Bearing Capacity ◽  
Laser Irradiation ◽  
Irradiation Time ◽  
Local Heating ◽  
Initial Period ◽  
Cylindrical Shells ◽  
Thin Wall ◽  
Stiffened Cylindrical Shells

Grid-stiffened cylindrical shells are widely applied in aviation and aerospace engineering. Bearing capacities of grid-stiffened cylindrical shells will be reduced by local heating. In this study, numerical simulation method is applied to deduce the temperature distribution of the grid-stiffened cylindrical shells subjected to high power laser irradiation. Temperature dependent aluminum alloy properties are fully considered in the process of numerical simulation. Comparing to smooth thin-wall cylindrical shells, the effect of ribs size to temperature distribution is studied. As the material properties varying with temperature, the temperature rising rate is higher at the initial period when cylindrical shell is subjected to laser irradiation. The temperature rising rate gradually reduces with irradiation time increasing. Buckling analysis was performed to obtain the buckling bearing capacity and the effect of local heating on grid-stiffened cylindrical shells subjected to local heating.

scholarly journals Convection regimes induced by local boundary heating in a liquid–gas system

2019 ◽  
Vol 873 ◽  
pp. 441-458 ◽  
Author(s):  
Victoria B. Bekezhanova ◽  
A. S. Ovcharova
Keyword(s):  
Gas Flow ◽  
Stokes Equations ◽  
Local Heating ◽  
Fluid Motion ◽  
Lower Boundary ◽  
Conjugate Problem ◽  
Temperature Fields ◽  
Layer System ◽  
Local Boundary ◽  
The Impact

In the framework of the complete formulation of the conjugate problem, the liquid–gas flow structure arising upon local heating using thermal sources is investigated numerically. The two-layer system is confined by solid impermeable walls. The Navier–Stokes equations in the Boussinesq approximation in the ‘streamfunction–vorticity’ variables are used to describe the media motion. The dynamic conditions at the interface are formulated in terms of the tangential and normal velocities, while the temperature conditions at the external boundaries of the system take into account the presence of local heaters. The influence of the number of heaters and heating modes on the dynamics and character of the appearing convective regimes is analysed. The steady and commutated heating modes for one and two heaters arranged at the lower boundary are investigated. The heating initiates convective and thermocapillary mechanisms causing the fluid motion. Transient regimes with the successive formation of two-vortex, quadruple-vortex and two-vortex flows are observed before the stabilization of the system in the uniform heating mode. A stable thermocapillary deflection appears at the interface above the heater. The commutated mode of heating entails oscillations of the interface with a change in the deflection form and the formation of travelling vortices in the fluids. The impact of particular mechanisms on the flow patterns is analysed. The paper presents typical distributions of the velocity and temperature fields in the system and the position of the interface for the considered cases.

Analysis and Design of Small Scale Pipe Forge Welding Process

2013 ◽  
Author(s):  
Junyan Liu ◽  
Ganesan S. Marimuthu ◽  
Per Thomas Moe
Keyword(s):  
High Speed ◽  
Pipe Wall ◽  
Local Heating ◽  
Welding Process ◽  
Axial Direction ◽  
Temperature Fields ◽  
Small Scale ◽  
Electromagnetic Modeling ◽  
Analysis And Design ◽  
Welding Machine

Shielded Active Gas Forge Welding is a high speed welding method for joining inter alia steel pipeline and casing. The process consists of a heating step, in which the bevels of the sections to be joined are heated locally to temperatures exceeding 1000 °C, and a subsequent forging step in which joining takes place by the application of a high axial force. In order to make possible cost-effective welding qualification and research a small scale forge welding machine has been developed. Down-scaling of the forge welding process should be carefully assessed in order to establish the limits of the process. In this paper two aspects of the forge welding process have been studied in detail by the use of finite element modeling and experiments: a) coupled thermal and electromagnetic modeling of heating and b) coupled thermo-mechanical modeling of forging. Special attention is given to the study of the limits of buckling of the pipe wall during forging. A high thermal gradient in the axial direction in the pipe wall facilitates local plastic deformation during forging and proper fusion of welds. For elongated temperature fields buckling is more likely to occur since the effective stiffness of the wall section is reduced. The limits of buckling depend on the wall thickness and diameter of section to be joined. While the forge welding process works very well for virtually all types of full scale pipeline and casing sections, buckling has been observed when joining very thin-walled small scale pipes. For welding of stainless steel small scale pipes local heating proves challenging. These challenges may be overcome by innovative welding machine design, and by carefully assessing welding process limitations. Certain physical limitations must still be considered.

Local tempering of welds in cylindrical shells with local heating

1975 ◽  
Vol 9 (3) ◽  
pp. 335-338
Author(s):  
G. V. Plyatsko ◽  
V. N. Maksimovich ◽  
Z. I. Goryacheva ◽  
D. P. Bolotyuk
Keyword(s):  
Local Heating ◽  
Cylindrical Shells

scholarly journals Entropy Generation Analysis of Natural Convection in Square Enclosures with Two Isoflux Heat Sources

2017 ◽  
Vol 7 (2) ◽  
pp. 1486-1495
Author(s):  
S. Z. Nejad ◽  
M. M. Keshtkar
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Local Heating ◽  
Heat Sinks ◽  
Temperature Fields ◽  
Entropy Generation Rate ◽  
Heat Sources ◽  
Minimum Entropy ◽  
Adiabatic Flow ◽  
Heater Length

This study investigates entropy generation resulting from natural convective heat transfer in square enclosures with local heating of the bottom and symmetrical cooling of the sidewalls. This analysis tends to optimize heat transfer of two pieces of semiconductor in a square electronic package. In this simulation, heaters are modeled as isoflux heat sources and sidewalls of the enclosure are isothermal heat sinks. The top wall and the non-heated portions of the bottom wall are adiabatic. Flow and temperature fields are obtained by numerical simulation of conservation equations of mass, momentum and energy in laminar, steady and two dimensional flows. With constant heat energy into the cavity, effect of Rayleigh number, heater length, heater strength ratios and heater position is evaluated on flow and temperature fields and local entropy generation. The results show that a minimum entropy generation rate is obtained under the same condition in which a minimum peak heater temperature is obtained.

Use of Renewable Energy for Local Heating of Piglets

2021 ◽  
Vol 3 (44) ◽  
pp. 104-110
Author(s):  
Stanislav S. Trunov ◽  
◽  
Dmitriy A. Tikhomirov ◽  
Aleksey V. Khimenko ◽  
Aleksey V. Kuz’michev ◽  
...  
Keyword(s):  
Thermal Energy ◽  
Local Heating ◽  
Thermoelectric Module ◽  
Heat Removal ◽  
Heat Pipes ◽  
Cold Season ◽  
Temperature Fields ◽  
Thermoelectric Modules ◽  
Suckling Piglets ◽  
Heat Released

The analysis of technologies and technical means of creating a temperature regime in the piglet location zone, where two different temperature fields must be created in the cold season: one for breeding pigs, the other for suckling piglets. The article considers the question of the use of thermoelectric modules and heat pipes as a source of thermal energy in local heating installations for suckling piglets. (Research purpose) There are proposed the functional and technological scheme of the installation for local heating of young animals with the use of thermoelectric modules and heat pipes. (Materials and methods) In the developed scheme, the thermal energy of the hot circuit of thermoelectric modules is used to heat the site on which the piglets are located. (Results and discussion) The heat of the cold circuit of the thermoelectric module assimilates the thermal energy of the removed ventilation air. For the effective operation of a thermoelectric installation for local heating of piglets, it is necessary that the cooling circuit, which absorbs thermal energy from the environment, be involved in some technological process for heat removal, for example, the heated ventilation air being removed. This leads to a significant increase in the efficiency of thermoelectric modules. At the same time, the installation will operate in the heat pump mode, since the amount of heat released in the heat exchanger of the hot circuit of the thermoelectric assembly exceeds the amount of electricity consumed from the network. (Conclusions) The article presents the sample of a thermoelectric installation was developed and its laboratory tests. The article describes the energy efficiency of the use of thermoelectric modules as energy converters in thermal technological processes.

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