Interferometric study of natural-convection heat transfer from a vertical flat plate with transverse roughness elements

Thesis/Dissertation · Wed Dec 31 23:00:00 EST 1986

OSTI ID:7255267

Bhavnani, S H

This research was undertaken to provide information on the nature of heat transfer from rough surfaces. An interferometric technique was used to experimentally measure local heat transfer coefficients. This method is essentially non-intrusive and therefore extremely suitable for the study of low-flux phenomena such as natural convection. Several different types of surfaces were studied - namely, repeated ribbed, stepped, and sinusoidal surfaces. The effects of parameters such as protuberance height-to-spacing ratios, amplitude of spacing, conductivity of ribs,leading edge geometry, and angle of inclination were studied. It was found that heat-transfer enhancement was possible in laminar natural convection using transverse roughness elements with proper sizing and shape selection. The heat transfer from the ribbed surfaces was found to be less than that from a plane flat plate of equal projected area. It was found that stepped surfaces could be used to improve the heat-transfer performance relative to a plane flat plate of equal projected area. The study indicated the presence of an optimum step-pitch-to-height ratio. The performance of sinusoidal surfaces was not significantly different from that of a plane fate plate of equal projected area at low amplitude-to-wavelength ratios.

• Research Organization: Iowa State Univ. of Science and Technology, Ames (USA)
• OSTI ID: 7255267
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
420800 -- Engineering-- Electronic Circuits & Devices-- (-1989)
CONVECTION
ELECTRONIC CIRCUITS
ENERGY TRANSFER
FLUID FLOW
HEAT TRANSFER
INTERFEROMETRY
LAMINAR FLOW
MASS TRANSFER
MEASURING METHODS
NATURAL CONVECTION
PLATES
ROUGHNESS
SURFACE PROPERTIES
SURFACES