Tube sizes

The heat-transfer coefficient depends on particle size distribution, bed voidage, tube size, etc. Thus a universal correlation to predict heat-transfer coefficients is not available. However, the correlation of Andeen and Ghcksman (22) is adequate for approximate predictions ... 

Units Pipe and Tubing Sizes and Ratings In this subsection pipe and tubing sizes are generally quoted in units of inches. To convert inches to millimeters, multiply by 25.4. Ratings are given in pounds. To convert pounds to kilograms, multiply by 0.454. 

Seamless copper tubing is sold in water-tubing sizes (ASTM B88 and B306). These sizes are identified by a standard size designation dimensionally Vh in less than the nominal outside diameter. The tubing is also sold as outside-diameter copper tubing (ASTM B280). 

Extracted from ANSI B16.22—1973 with permission of the publisher, the American Society of Mechanical Engineers, New York. ( F — 32) 9 = C to convert inches to millimeters, multiply by 25.4 to convert pounds-force per square inch to megapascals, multiply by 0.006895. f Standard water-tubing sizes. 

Bimetallic Tubes When corrosive requirements or temperature conditions do not permit the use of a single alloy for the tubes, bimetalhc (or duplex) tubes may be used. These can be made from almost anv possible combination of metals. Tube sizes and gauges can be varied. For thin gauges the wall thickness is generally divided equally between the two components. In heavier gauges the more expensive component may comprise from a fifth to a third of the total thickness. 

Forced Circulation System—Using foreed eireulation in a waste heat reeovery system allows the use of smaller tube sizes with inherent inereased heat transfer eoeffieients. Flow stability eonsiderations must be addressed. The reeireulating pump is a eritieal eomponent from a reliability standpoint and standby (redundant) pumps must be eonsidered. In any event, great eare must go into preparing speeifieations for this pump. 

From the requirement that a smooth crossover between Eqs. (29) and (31) for t = rR should take place, one can estimate the diffusion constant as Dn oc Wf /N, i.e., in the scaling limit Dj does not depend on the tube size D. 

Figure 10-9C. Coil Assembly for bare tube Heliflow exchanger. Tube sizes range from V4 -V4 in. O.D. Tube-side manifold connections are shown for inlet and outlet fluid. (Used by permission Graham Manufacturing Company, Inc., Bui. HHE-30 1992.)...

Kj, Kg, Kj, Kj = Constants depending on the tube size and layout. Use the following table. 

Radius of Bend = 2 V2 times tube O.D. for all pitches and tube sizes Pie shape layout Pie shape layout Vertical baffle layout Vertical baffle layout... 

Tube Passes Two or Four Tube Size 8 Pitch 3/4"on 5/l6 A... 

Figure 10-25A. Tubesheet layout for U-tube exchanger. Tube passes two or four. Tube sizes and pitch % in. on in.A. Radius of bend 2Vj X tube diameter.

Tube Sheet Layout FIXED TUBE SHEET EXCHANGER (Also Non-Removable Flaating Head) Tube Passes Two Tube Size a Pitch 3/4 on I5/I6"A... 

Figure 10-25F. Fixed tubesheet layout (also nonremovable floating head). Tube passes two. Tube size and pitch V4 in. on in.A.

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