Heat transfer from flame impingement normal to a plane surface.

Format:

Book

Thesis/Dissertation

Author/Creator:

Baukal, Charles Edward, Jr.

Contributor:

Gebhart, Benjamin, advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Mechanical engineering.

0548.

Penn dissertations--Mechanical engineering.

Mechanical engineering--Penn dissertations.

Penn dissertations--Applied mechanics.

Applied mechanics--Penn dissertations.

Penn dissertations--Mechanical engineering and applied economics.

Mechanical engineering and applied economics--Penn dissertations.

Local Subjects:

Penn dissertations--Mechanical engineering.

Mechanical engineering--Penn dissertations.

Penn dissertations--Applied mechanics.

Applied mechanics--Penn dissertations.

Penn dissertations--Mechanical engineering and applied economics.

Mechanical engineering and applied economics--Penn dissertations.

0548.

Physical Description:

208 pages

Contained In:

Dissertation Abstracts International 57-04B.

System Details:

Mode of access: World Wide Web.

text file

Summary:

The purpose of this research was to determine the importance of several heat transfer mechanisms, for flames impinging normal to a plane surface. These mechanisms included forced convection, thermochemical heat release from the cooling of dissociated species, and nonluminous gaseous radiation. The oxidizer composition ($\Omega$ = 0.21 to 1.00), axial (L = 0.5 to 6.0) and radial (R$\rm\sb{eff}$ = 0.16 to 1.04) position of the surface, burner firing rate ($q\rm\sb{f}$ = 5 to 25 kW), surface properties (untreated, polished, blackened, alumina-coated, and platinum-coated), composition (brass, copper, and stainless) and thickness (1.45 to 9.11 mm) were investigated. A burner ($d\rm\sb{n}$ = 38.5 mm) was developed that could use an oxidizer ranging from air to pure O$\sb2$. In the experiments, a round flame impinged onto a water-cooled metal disk ($d\rm\sb{b}$ = 135 mm), which was segmented into six concentric calorimetric rings. The experimental results showed that flame radiation increased by up to 164% by varying $\Omega$ from 0.28 to 1.00. However, this nonluminous flame radiation was less than 10% of the total heat flux to the target. The thermochemical heat release mechanism was predominantly of the equilibrium type. The target material composition, thickness, cooling-water flow rates, and surface conditions had only minimal effects on the heat flux. The heat flux increased by 78 to 280% by increasing the firing rate from 5 to 25 kW. The flux increased 54 to 230% by increasing $\Omega$ from 0.30 to 1.00. For high $\Omega$ flames, the peak flux always occurred at the stagnation point and the closest axial spacing. For low $\Omega$ flames, the peak flux occurred at about L = 1 to 2 and a radial spacing of about R$\rm\sb{eff}$ = 0.6. Existing semi-analytic solutions and empirical correlations failed to accurately predict the experimental data. A new empirical correlation has been recommended. This is the first study to investigate the effects of the target composition and thickness, the cooling-water flow rate, the surface emissivity and catalyticity, and the range of oxidizer compositions between air and pure O$\sb2$. It is also the first to report flame radiation measurements from oxygen-enhanced flames.

Notes:

Thesis (Ph.D. in Mechanical Engineering) -- University of Pennsylvania, 1995.

Source: Dissertation Abstracts International, Volume: 57-04, Section: B, page: 2812.

Adviser: Benjamin Gebhart.

Local Notes:

School code: 0175.

Access Restriction:

Restricted for use by site license.