Pressure drop Inside tubes

For pressure drop inside tubes, d is 0.046 and F is the fluid-flow path length. Across tubes banks, a is 0.75 and F is the product of the number of tube rows and the number of fluid passes across the tube bank. The physical property term is again tabulated after being normalised so that the lowest value is approximately unity. 

Pressure drop. If the pressure drop of one fluid is critical and must be accurately predicted, then place that fluid inside the tubes. Pressure drop inside tubes can be calculated with less error, as the pressure drop in the shell will deviate widely from theoretical values depending upon the shell leakage clearances in the particular exchanger. 

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... 

Frictiona.1 Pressure Drop. The frictional pressure drop inside a heat exchanger results when fluid particles move at different velocities because of the presence of stmctural walls such as tubes, shell, channels, etc. It is calculated from a weU-known expression of... 

The pressure drop inside the draft tube is more complicated because it involves acceleration of solid particles from essentially zero vertical velocity. However, the model for calculating the pressure drop in vertical pneumatic conveying lines suggested by Yang (1977) can be applied. The acceleration length can be calculated from numerical integration of the following equation. 

Select the method to be used. For two-phase flow, the friction pressure drop inside a tube can be calculated using the equation [31]... 

In gas permeation, a gas species is separated based mainly on its permeability in hollow fiber and spiral wound membranes. The hollow fiber systems can have an inside diameter up to 200 xm and hence very large surface-to-volume ratios, but high pressure drops inside the tubes. The basic flow equation for a species / is... 

L. B. Evans and S. W. Churchill, The Effect of Axial Promoters on Heat Transfer and Pressure Drop Inside a Tube, Chem. Eng. Prog. Symp. Ser. 59 (41) 36-46,1963. 

Tube-Fin Heat Exchangers. The pressure drop inside a circular tube is computed using Eq. 17.65 with proper values of/factors (see equations in Tables 17.14 and 17.16) and Kc and Ke from Fig. 17.35 for circular tubes. 

Fluid Temperature, °C Minimum velocity, m/s Pumping rate factor Pressure drop factor Outside tubes Inside tubes... 

Pressure drop during condensation inside horizontal tubes can be computed by using the correlations for two-phase flow given in Sec. 6 and neglec ting the pressure recoveiy due to deceleration of the flow. 

Because finned tubes of the low-fm design are standard tubes, the inside heat exchange and pressure drop performance will be the same as determined for plain or bare tubes. Use the appropriate information from earlier design sections. 

The dirty gas flows upward into the filter bag and the dust collects on the inside surface. When the pressure drop rises to a predetermined upper limit due to dust accumulation, the gas flow is stopped and the shaker is operated. This process dislodges the dust, which falls into a hopper located below the tube sheet. 

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