Friction pressure drop coefficient

In the macroscopic heat-transfer term of equation 9, the first group in brackets represents the usual Dittus-Boelter equation for heat-transfer coefficients. The second bracket is the ratio of frictional pressure drop per unit length for two-phase flow to that for Hquid phase alone. The Prandd-number function is an empirical correction term. The final bracket is the ratio of the binary macroscopic heat-transfer coefficient to the heat-transfer coefficient that would be calculated for a pure fluid with properties identical to those of the fluid mixture. This term is built on the postulate that mass transfer does not affect the boiling mechanism itself but does affect the driving force. 

Frictional pressure drop, in heat exchanger design, 13 260-261 Friction and Wear Databank, 15 205 Friction coefficients, 10 178 11 749, 750 13 247... 

Estimation of Individual Heat Transfer Coefficients and Frictional Pressure Drop... 

An enormous amount of experimental work on convective heat transfer and skin-friction pressure drop has been reported during the 1900s. This has been accompanied by theoretied developments. For laminar flow, heat transfer coefficients and friction factors for weD-... 

The friction factor, f and the pressure-drop coefficient, C are determined from Figure 12-13. The friction factor is plotted against a modified Reynolds number in which... 

Rgure 12-13. Correlation for estimating friction factor and pressure drop coefficient for use in calculation of pressure drop of gas flowing through beds of granular adsorbents. DataofUOP(miB)... 

Friction Coefficient. In the design of a heat exchanger, the pumping requirement is an important consideration. For a fully developed laminar flow, the pressure drop inside a tube is inversely proportional to the fourth power of the inside tube diameter. For a turbulent flow, the pressure drop is inversely proportional to D where n Hes between 4.8 and 5. In general, the internal tube diameter, plays the most important role in the deterrnination of the pumping requirement. It can be calculated using the Darcy friction coefficient,, defined as... 

The sensitivity of the pressure drop to the coefficient of solids-surface friction /j.f may well account for the wide scatter in the results shown earlier in Figure 5.10. Unfortunately this quantity has been measured by only very few investigators. It must be emphasised that in the design of any hydraulic transport system it is extremely important to have a knowledge of the coefficient of friction. 

This meter may thus be considered as an orifice meter with a variable aperture, and the formulae already derived are therefore applicable with only minor changes. Both in the orifice-type meter and in the rotameter the pressure drop arises from the conversion of pressure energy to kinetic energy and from frictional losses which are accounted for in the coefficient of discharge. The pressure difference over the float —AP. is given by ... 

The rate of flow of water in a 150 mm diameter pipe is measured with a venturi meter with a 50 mm diameter throat. When the pressure drop over the converging section is 100 mm of water, the flowrate is 2.7 kg/s. What is the coefficient for the converging cone of the meter at feat flowrate and what is the head lost due to friction if the total loss of head over the meter is 15 mm water, what is the coefficient lor the diverging cone ... 

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