McAdams

McAdams (Heat Transmission, 3d ed., McGraw-HiU, New York, 1954) gives various forms of transient difference equations and methods of solving transient conduction problems. The availabihty of computers and a wide variety of computer programs permits virtually routine solution of complicated conduction problems. 

For the turbulent flow of water in layer form down the walls of vertical tubes the dimensional equation of McAdams, Drew, and Bays [Trans. Am. Soc. Mech. Eng., 62, 627 (1940)] is recommended ... 

Equation (5-47b) is based on the work of Bays and McAdams [Jnd. Eng. Chem., 29, 1240 (1937)]. The significance of the term L is not clear. When L = 0, the coefficient is definitely not infinite. When E is large and the fluid temperature has not yet closely approached the wall temperature, it does not appear that the coefficient should necessarily decrease. Within the finite limits of 0.12 to 1.8 m (0.4 to 6 ft), this equation should give results of the proper order of magnitude. 

Cascade coolers are a series of standard pipes, usually manifolded in parallel, and connected in series by vertically or horizontally oriented U-bends. Process fluid flows inside the pipe entering at the bottom and water trickles from the top downward over the external pipe surface. The water is collected from a trough under the pipe sections, cooled, and recirculated over the pipe sections. The pipe material can be any of the metallic and also glass, impeiMous graphite, and ceramics. The tubeside coefficient and pressure drop is as in any circular duct. The water coefficient (with Re number less than 2100) is calculated from the following equation by W.H. McAdams, TB. Drew, and G.S. Bays Jr., from the ASME trans. 62, 627-631 (1940). 

Energy Laws Several laws have been proposed to relate size reduction to a single variable, the energy input to the mill. These laws are encompassed in a general differential equation (Walker, Lewis, McAdams, and Gilliland, Principles of Chemical Engineering, 3d ed., McGraw-HiU, New York, 1937) ... 

Even the good heat transfer conditions turned out to be false, however, if the correlation derived for single cylinders by McAdams (1954) were extrapolated to Rep < 100. Nelson and Galloway (1975) pointed out that at low Reynolds numbers the real heat transfer coefficient could be four... 

McAdams, W.FI., 1954, Heat Transmission, p. 259, McGraw-Hill, New York. 

Figure 10-51. Convection inside film coefficient for gases and low viscosity fluids inside tubes—heating and cooling. (Used by permission McAdams, W. H. Heat Transmission, 2"= Ed., 1942. McGraw-Hill, Inc. All rights reserved.)...

Figure 10-67A has been initially represented by McAdams from several investigators. This figure represents the mean coefficient for the entire vertical tube for two values of the Prandtl number, Pq, which = cp/k. 

Note that the break at Point A on Figure 10-67B at Re = 2,100 indicates where the film is believed to become turbulent. McAdams discusses the two regions on the figure, streamlined at the top and turbulent on the way down, with a transition region in between ... 

McAdams and Kem bodi suggest the same relationship for condensation on the outside of vertical tubes ... 

Figure 10-67B. Correlation of McAdams representing the condensing film coefficient on the outside of vertical tubes, integrated for the entire tube length. This represents the streamline transition and turbulent flow conditions for Prandtl numbers 1 and 5. Do not extrapolate Prandtl numbers, Pr beyond 5. (Used by permission Engineering Data Book II 1984, Wolverine Tube, Inc.)...

When a liquid is vaporized in horizontal tubes, the inidal overall coefficient is several dmes the value for forced convecdon single-phase heat transfer. As the amount of vapor increases up to 100%, the coefficient falls off, down to a gas convecdon coefficient. The work of McAdams is some of the limited literature in this type of heat transfer. 

Determine outside film coefficient for spray or drip cooling using the equation of McAdams as presented hy Kem. ... 

Fig. 8.74 Stress and corrosion time required to produce given percentage reduction (e.g. 15%) of fatigue limit due to corrosion alone (after McAdam )...

The data on which Fig. 8.74 is based are for tests carried out in carbonate well-water. McAdam made the further interesting discovery that if mild steel were tested in condenser water and a similar graph constructed, the set of contours corresponded more closely to the right-hand side of Fig. 8.74, i.e. the behaviour of mild steel in condenser water was similar to that of Monel in carbonate water. The apparent universality of this diagram is an interesting observation, but it has not provoked a basic theory of corrosion fatigue. 

Some of the investigations involving electrochemical measurements have been concerned with relating easily determined quanities such as corrosion potential and corrosion current with the behaviour of a material in corrosion fatigue, so that this behaviour can be rapidly assessed without the necessity of the laborious collection of data which was the feature of McAdam s approach. Endo and Komai have derived an expression relating the increase... 

McAdam, D. J., Influence of water composition in stress corrosion , Proc. ASTM,3, part II, 259-278 (1931)... 

---