322,932 research outputs found
"BOILING HEAT TRANSFER AROUND A CYLINDRICAL HEATER IMPINGED BY A SLOT JET"
No full textThe results of an experimental study of heat transfer, in two-phase condition, from a circular cylinder to a submerged slot jet of water are reported. In particular the trends of local temperature of the heater external wall versus jet exit velocity are shown for different values of the angle from the front stagnation point, θ. At every value of θ this trend is monotonically decreasing with increasing velocity, without the irregularity found in single phase. The dependence of the temperature and the heat transfer coefficient on the angular coordinate is very weak. The simultaneous presence of boiling phenomena near the rear stagnation point and the jet impingement mechanisms near the stagnation point can explain this trend
Local nusselt number at a cylinder cooled by a slot jet of water
No full textThe results of an experimental study of heat transfer from a circular cylinder to a slot jet of water are reported. In particular the trends of local Nusselt numbers versus Re and Pr are shown for three different values of the angle from the front stagnation point, θ. At θ=0° this trend is monotonically increasing with increasing Re, on the contrary at θ=90° and θ=180° the trends exhibit two irregularities in the neighborhood of Re=9.5×103 and 1.5×104 respectively. Also the local Nusselt numbers versus θ are reported for several values of Re: the heat transfer coefficient always presents a minimum for 70° < θ < 100°
" HEAT TRANSFER AND FLOW PATTERN AT A CYLINDER IMPINGED BY A SLOT JET DURING INCIPIENT AND NUCLEATE BOILING"
No full textThe heat transfer due to a submerged slot jet of water impinging on a circular cylinder in cross flow was experimentally studied in the region of incipient and fully developed nucleate boiling. The diameter of the cylinder and the width of the jet are the same-namely, 3 mm. The heat flux ranged from 4 x 10(4) to 1.5 x 10(6) W/m(2). The effects of the jet velocity and of the fluid subcooling were investigated in the range 0.37 less than or equal to v 1.11 m/s and 0 less than or equal to (Delta T)(sub) less than or equal to 15 K, both in upward and downward flow. The results showed that the influence of these parameters is limited to the region of incipient boiling, whereas, in fully developed boiling, all the boiling curves merge into a single one. A photographic study of the bubble flow pattern evidenced a different behavior with respect to cylinders in uniform cross flow
Influence of Streamwise Molecular Heat Conduction on the Heat Transfer Coefficient for Liquid Metals in Turbulent Flow between Parallel Plates
No full textThe energy equation for mechanically fully developed turbulent flow between parallel plates is numerically solved taking into account the term of streamwise heat conduction. Solutions are presented for Re = 7060 and 73620, and for Pr ranging from 0.001 to 0.1. Generally the influence of the streamwise molecular conduction results in a remarkable decrease of the Nusselt number in the thermal inlet.
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Copyright © 1980 by ASM
CARATTERIZZAZIONE DEL RUMORE DI SORGENTI STRADALI: ESPERIENZE NELLE CITTA’ DI PISA E LUCCA
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