Trapezoidal ducts

A trapezoidal duct is displayed in the inset of Fig. 5.50. Fully developed laminar flow and the heat transfer characteristics of trapezoidal ducts have been analyzed by Shah [172]. The fully developed /Re, NuHn and NuH2 are given in Figs. 5.50 and 5.51. Farhanieh and Sunden [276] numerically investigated the laminar flow and heat transfer in the entrance region of trapezoidal ducts. The fully developed values off Re, K(°°), and Nu were in accordance with the results from Shah [172]. 

FIGURE 5.50 Fully developed/Re and K(< =) for laminar flow in a trapezoidal duct [172]. 

Chiranjivi and Rao [277] experimentally obtained a correlation for laminar and turbulent flow in trapezoidal ducts with one side heated, which is expressed as ... 

B. Farhanieh, and B. Sunden, Three Dimensional Laminar Flow and Heat Transfer in the Entrance Region of Trapezoidal Ducts, Int. J. Numerical Methods in Fluids, (13) 537-556,1991. 

Chapter 4 is devoted to single-phase heat transfer. Data on heat transfer in circular micro-tubes and in rectangular, trapezoidal and triangular ducts are presented. Attention is drawn to the effect of energy dissipation, axial conduction and wall roughness on the thermal characteristics of flow. Specific problems connected with electro-osmotic heat transfer in micro-channels, three-dimensional heat transfer in micro-channel heat sinks and optimization of micro-heat exchangers are also discussed. 

Heat Transfer in Rectangular, Trapezoidal and Triangular Ducts... 

When a sound pressure wave impinges on the ear, it is amplified by the external auditory meatus and causes the tympanic membrane to vibrate in a characteristic manner. This vibration is transformed by the auditory ossicles of the middle ear into movements of the stapedial footplate. These movements create pressure waves in the fluids of the inner ear which displace the basilar membrane of the cochlear duct and cause the hair cells located on the top of the basilar membrane to generate electrical potentials. This potential elicits impulses in the auditory nerve. After the auditory nerve, the nerve impulses are transmitted through the cochlear nuclei, the trapezoid body, the... 

Adhesion of Particles to Bottom of Air Duct. Dust particles will not fall to the bottom of a duct (and hence there will be no dust adhesion) if the vertical pulsating velocity Vy of the air flow is greater than the terminal (free-fall) velocity of the particles in air, i.e., if Vy > Uff. If we know Vy and its relation to the flow velocity, we can calculate the minimum air-flow velocity to prevent the settling of dust. Ryzhenko [242] found that for particles with diameters smaller than 10 ixm in moving air, the allowable velocities in air ducts with circular, rectangular, or trapezoidal sections, i.e., Vq, v, and are expressed by the formula... 

---