SIMULTANEOUSLY DEVELOPING FLOW AND HEAT TRANSFER IN THE ENTRANCE REGION OF ELLIPTICAL DUCTS

1986 ◽  
Author(s):  
C. W. Rapley ◽  
R. Stainsby ◽  
A. I. C. Webb
Keyword(s):  
Heat Transfer ◽  
Entrance Region ◽  
Flow And Heat Transfer ◽  
Developing Flow

Turbulent Flow and Heat Transfer in the Entrance Region of a Parallel Wall Passage

1969 ◽  
Vol 184 (1) ◽  
pp. 697-712 ◽  
Author(s):  
J. Byrne ◽  
A. P. Hatton ◽  
P. G. Marriott
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Entrance Region ◽  
Fully Developed Flow ◽  
Law Of The Wall ◽  
Flow And Heat Transfer ◽  
Developing Flow ◽  
Boundary Layer Development ◽  
Parallel Wall ◽  
Made In

Measurements of boundary layer development and heat transfer were made in the entrance region of a parallel passage and compared with a computer solution based on the law of the wall. Little difference was found between the heat transfer, both measured and predicted, with a developing flow and that predicted with a fully developed flow. The experiments also show that boundary layer parameters, such as momentum thickness, do not approach their fully developed values asymptotically.

A Comparative Study of DES and URANS in a Two-Pass Internal Cooling Duct With Normal Ribs

2005 ◽  
Author(s):  
Aroon K. Viswanathan ◽  
Danesh K. Tafti
Keyword(s):  
Heat Transfer ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Internal Cooling ◽  
Detached Eddy Simulation ◽  
Mean Flow ◽  
Streamline Curvature ◽  
Eddy Simulation ◽  
Flow And Heat Transfer ◽  
Developing Flow

The capabilities of the Detached Eddy Simulation (DES) and the Unsteady Reynolds Averaged Navier-Stokes (URANS) versions of the 1988 κ-ω model in predicting the turbulent flow field and the heat transfer in a two-pass internal cooling duct with normal ribs is presented. The flow is dominated by the separation and reattachment of shear layers; unsteady vorticity induced secondary flows and strong streamline curvature. The techniques are evaluated in predicting the developing flow at the entrance to the duct and downstream of the 180° bend, fully-developed regime in the first pass, and in the 180° bend. Results of mean flow quantities, secondary flows, friction and heat transfer are compared to experiments and Large-Eddy Simulations (LES). DES predicts a slower flow development than LES, while URANS predicts it much earlier than LES computations and experiments. However it is observed that as fully developed conditions are established, the capability of the base model in predicting the flow and heat transfer is enhanced by switching to the DES formulation. DES accurately predicts the flow and heat transfer both in the fully-developed region as well as the 180° bend of the duct. URANS fails to predict the secondary flows in the fully-developed region of the duct and is clearly inferior to DES in the 180° bend.

Large Eddy Simulation of Flow and Heat Transfer in the Developing Flow Region of a Rotating Gas Turbine Blade Internal Cooling Duct With Coriolis and Buoyancy Forces

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Evan A. Sewall ◽  
Danesh K. Tafti
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Flow Region ◽  
Internal Cooling ◽  
Heat Transfer Augmentation ◽  
Flow And Heat Transfer ◽  
Buoyancy Parameter ◽  
Developing Flow ◽  
Large Eddy

The problem of accurately predicting the flow and heat transfer in the ribbed internal cooling duct of a rotating gas turbine blade is addressed with the use of large eddy simulations (LES). Four calculations of the developing flow region of a rotating duct with ribs on opposite walls are used to study changes in the buoyancy parameter at a constant rotation rate. The Reynolds number is 20,000, the rotation number is 0.3, and the buoyancy parameter is varied between 0.00, 0.25, 0.45, and 0.65. Previous experimental studies have noted that leading wall heat transfer augmentation decreases as the buoyancy parameter increases with low buoyancy, but heat transfer then increases with high buoyancy. However, no consistent physical explanation has been given in the literature. The LES results from this study show that the initial decrease in augmentation with buoyancy is a result of larger separated regions at the leading wall. However, as the separated region spans the full pitch between ribs with an increase in buoyancy parameter, it leads to increased turbulence and increased entrainment of mainstream fluid, which is redirected toward the leading wall by the presence of a rib. The impinging mainstream fluid results in heat transfer augmentation in the region immediately upstream of a rib. The results obtained from this study are in very good agreement with previous experimental results.

scholarly journals Developing Flow and Heat Transfer in Strongly Curved Ducts of Rectangular Cross Section

1980 ◽  
Vol 102 (2) ◽  
pp. 285-291 ◽  
Author(s):  
G. Yee ◽  
R. Chilukuri ◽  
J. A. C. Humphrey
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Numerical Study ◽  
Rectangular Cross Section ◽  
Flow And Heat Transfer ◽  
Computational Mesh ◽  
Developing Flow ◽  
Duct Geometry ◽  
Curved Ducts

A numerical study of heat transfer in 90 deg, constant cross section curved duct, steady, laminar, flow is presented. The work is aimed primarily at characterizing the effects on heat transfer of duct geometry and entrance conditions of velocity and temperature by considering, especially, the role of secondary motions during the developing period of the flow. Calculations are based on fully elliptic forms of the transport equations governing the flow. They are of engineering value and are limited in accuracy only by the degree of computational mesh refinement. A comparison with calculations based on parabolic equations shows how the latter can lead to erroneous results for strongly curved flows. Buoyant effects are excluded from the present study so that, strictly, the results apply to heat transfer flows in the absence of gravitational forces such as arise in spacecraft.

scholarly journals Numerical Investigation on the Fluid Flow and Heat Transfer in the Entrance Region of Wavy Channel

2013 ◽  
Vol 36 ◽  
pp. 76-85 ◽  
Author(s):  
Nabou Mohamed ◽  
Biara Ratiba Wided ◽  
El Mir Mohamed ◽  
Missoum Abd el karim ◽  
Bouanini Mohamed
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Investigation ◽  
Entrance Region ◽  
Wavy Channel ◽  
Flow And Heat Transfer
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