Surfaces inclined

Two cases are considered. The first, the laminar flow of a thin film down an inclined surface, is important in the heat transfer from a condensing vapour where the main resistance to transfer lies in the condensate film, as discussed in Chapter 9 (Section 9.6.1). The second is the flow in open channels which are frequently used for transporting liquids down a slope on an industrial site. 

HEAT TRANSFER IN THE CONDENSATION OF VAPOURS 9.6.1. Film coefficients for vertical and inclined surfaces... 

Liquid flows down an inclined surface as a film. On what variables will the thickness of the liquid film depend Obtain the relevant dimensionless groups. It may be assumed that the surface is sufficiently wide for edge effects to be negligible. 

The wave amplitude on an inclined surface should be smaller than on a vertical surface for the same flow rate and liquid properties, while the wavelength should be greater on the inclined surface. 

Surfactants also play a major role in reducting droplet sliding and increasing spray retention. When a drop impinges on an inclined surface (such as a leaf surface), it starts to slide as a result of gravity. During this process,... 

Flow with a free surface is discussed in Section 3.6 and the particular case of laminar flow down an inclined surface in Section 3.6.1. For a flow of liquid of depth 8, width w and density p down a surface inclined at an angle 0 to the horizontal, a force balance in the x direction (parallel to the surface) may be written. The weight of fluid flowing down the plane at a distance y from the free surface is balanced by the shear stress at the plane. For unit width and unit height ... 

The dynamic liquid holdup h[Pg.412]

Vliet, G.C., Natural Convection Local Heat Transfer on Constant Heat Rux Inclined Surfaces , J. Heat Transfer, Vol. 9, pp. 511-516, 1969. 

Pera, L. and Gebhart, B., "Natural Convection Boundary Layer Flow Over Horizontal and Slightly Inclined Surfaces , Int. J. Heat Mass Transfer. Vol. 16, p. 1131. 1973. 

Extensive experiments have been reported in Refs. 25, 26, and 39 for free convection from vertical and inclined surfaces to water under constant-heat-... 

Section 7-7 discusses an extension of these equations to inclined surfaces. 

Uncertainties still remain in the prediction of free convection from inclined surfaces, and an experimental-data scatter of 20 percent is not unusual for the empirical relations presented above. 

Therefore, for laminar flow, we suggest that inclined surfaces be treated with the simple substitution indicated in Eq. (9-19). 

Chen, T.S. and Moutsoglu. (1979). Wave instability of mixed convection flow on inclined surfaces. Num. Heat Transfer, 2 497-509. 

Haaland, S.E. and Sparrow, E.M. (1973). Vortex instability of natural convection flows on inclined surfaces, Int. J. Heat Mass Transfer 16 2355-2367. 

Two forms of Eq. (6-21) have been proposed. For low values of the Reynolds number of liquid flow, liquid holdup in a packed column can be predicted by consideration of laminar liquid flow down inclined surfaces against a pressure gradient In this viscous flow regime,... 

In the bubble formation from an inclined surface, however, the bubble development and the bubble detachment processes are decoupled because a developing bubble could drift out of the orifice due to the component of the buoyancy parallel to the inclined surface. Once a sessile bubble drift out of the orifice, the bubble development ceases because no air is fed into a sliding bubble. Since the bubble development and detachment are decoupled, the flow rate of air becomes an important factor, which controls the frequency of sliding bubble... 

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