scholarly journals Natural Convection in a Trapezoidal Enclosure with Wavy Top Surface

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Pensiri Sompong ◽  
Supot Witayangkurn
Keyword(s):  
Natural Convection ◽  
Temperature Distribution ◽  
Flow Field ◽  
Element Model ◽  
Darcy Number ◽  
Model Builder ◽  
Small Influence ◽  
Study Results ◽  
Flow Intensity ◽  
Trapezoidal Enclosure

The effects of various parameters, Rayleigh number (Ra), Darcy number (Da), and wave amplitude (a), on natural convection inside a trapezoidal enclosure with wavy top surface are studied. The enclosure is filled with seawater having Prandtl number (Pr) of 7.2 and uniformly heated on bottom and partially heated on inclined boundaries. The flow field and temperature distribution are observed when interested parameters are chosen for Ra = 104, 105, and 106, Da = 10−5, 10−4, and 10−3, anda=0.9, 1, and 1.1. FlexPDE, a finite element model builder, is used to solve the governing equations to obtain the numerical results displayed by streamlines and isotherms. From the study results, convection motion is affected by different parameters in which the increase in flow intensity and temperature distribution can be seen at higher Rayleigh and Darcy numbers. The wavy top surface has small influence on the flow field and temperature distribution compared to the influence of Rayleigh and Darcy numbers.

scholarly journals A numerical investigation of a buoyancy driven flow in a semi-porous cavity: comparative effects of ramped and isothermal wall conditions

2013 ◽  
Vol 61 (2) ◽  
pp. 103-111 ◽  
Author(s):  
Pallath Chandran ◽  
Nirmal C. Sacheti ◽  
Ashok K. Singh
Keyword(s):  
Natural Convection ◽  
Temperature Distribution ◽  
Nonlinear Partial Differential Equations ◽  
Darcy Number ◽  
Two Dimensional ◽  
Function Formulation ◽  
Isotropic Porous Material ◽  
Vertical Walls ◽  
Isothermal Wall ◽  
Stream Function Formulation

Abstract Steady two-dimensional natural convection taking place in a rectangular cavity, partially filled with an isotropic porous material, has been investigated numerically using an ADI method. It is assumed that one of the vertical walls of the cavity has a ramped temperature distribution. The vorticity-stream function formulation has been used to solve the set of nonlinear partial differential equations governing the flows in the clear region and the adjoining porous region. The effects of Darcy number and Rayleigh number have been discussed in detail.

EFFECTS OF HEAT FLUX ON NATURAL CONVECTION OFWATER-BASED NANOFLUIDS IN A TRAPEZOIDAL ENCLOSURE

2018 ◽  
Vol 49 (13) ◽  
pp. 1299-1321
Author(s):  
Xiaofeng Wang ◽  
Juntao Wang ◽  
Weizhong Dai
Keyword(s):  
Heat Flux ◽  
Natural Convection ◽  
Trapezoidal Enclosure

Fundamental Issues and Recent Advancements in Analysis of Aircraft Brake Natural Convective Cooling

1998 ◽  
Vol 120 (4) ◽  
pp. 840-857 ◽  
Author(s):  
M. P. Dyko ◽  
K. Vafai
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Field ◽  
Three Dimensional ◽  
Convective Cooling ◽  
Cooling Flow ◽  
Physical Mechanisms ◽  
Braking System ◽  
Flow And Heat Transfer ◽  
Convection Cooling

A heightened awareness of the importance of natural convective cooling as a driving factor in design and thermal management of aircraft braking systems has emerged in recent years. As a result, increased attention is being devoted to understanding the buoyancy-driven flow and heat transfer occurring within the complex air passageways formed by the wheel and brake components, including the interaction of the internal and external flow fields. Through application of contemporary computational methods in conjunction with thorough experimentation, robust numerical simulations of these three-dimensional processes have been developed and validated. This has provided insight into the fundamental physical mechanisms underlying the flow and yielded the tools necessary for efficient optimization of the cooling process to improve overall thermal performance. In the present work, a brief overview of aircraft brake thermal considerations and formulation of the convection cooling problem are provided. This is followed by a review of studies of natural convection within closed and open-ended annuli and the closely related investigation of inboard and outboard subdomains of the braking system. Relevant studies of natural convection in open rectangular cavities are also discussed. Both experimental and numerical results obtained to date are addressed, with emphasis given to the characteristics of the flow field and the effects of changes in geometric parameters on flow and heat transfer. Findings of a concurrent numerical and experimental investigation of natural convection within the wheel and brake assembly are presented. These results provide, for the first time, a description of the three-dimensional aircraft braking system cooling flow field.

Process Modeling in Laser Deposition of Multilayer SS410 Steel

2007 ◽  
Vol 129 (6) ◽  
pp. 1028-1034 ◽  
Author(s):  
Liang Wang ◽  
Sergio Felicelli
Keyword(s):  
Phase Transformation ◽  
Temperature Distribution ◽  
Three Dimensional ◽  
Element Model ◽  
Traverse Speed ◽  
Processing Parameters ◽  
Dimensional Finite Element ◽  
Net Shaping ◽  
Three Dimensional Finite Element ◽  
Continuous Cooling Transformation Diagram

A three-dimensional finite element model was developed to predict the temperature distribution and phase transformation in deposited stainless steel 410 (SS410) during the Laser Engineered Net Shaping (LENS™) rapid fabrication process. The development of the model was carried out using the SYSWELD software package. The model calculates the evolution of temperature in the part during the fabrication of a SS410 plate. The metallurgical transformations are taken into account using the temperature-dependent material properties and the continuous cooling transformation diagram. The ferritic and martensitic transformation as well as austenitization and tempering of martensite are considered. The influence of processing parameters such as laser power and traverse speed on the phase transformation and the consequent hardness are analyzed. The potential presence of porosity due to lack of fusion is also discussed. The results show that the temperature distribution, the microstructure, and hardness in the final part depend significantly on the processing parameters.

Sign in / Sign up

Export Citation Format

Share Document