Ashell-and-tube heat exchanger with single shell and two passes tube (1-2) uses hot water on the tube side to heat oil on the shell side. there are 20 tube passes made of copper have inner and outer diameters of 20 and 24 mm and the length of the heat exchanger is 3 m. water enters each tube at a rate of 0.2 kg/s at 87 °c and leaves at (a) calculate the convective heat transfer coefficient of the tube inner side. (b) calculate the overall heat transfer coefficient based on the pipe outer area if the shell side convective coefficient is 875 w/(m^2k). (c) calculate the total heat exchange area available (d) calculate the total heat load of the heat exchanger (e) calculate lmtd if the value for f is 0.9

The allotropes of carbon include a variety of structures that include three-dimensional tetrahedral lattices, planes of hexagonal rings, cylindrical tubes of hexagonal rings, and spheres of five- and six-membered rings. similar shapes of network covalent atomic solids are possible with carbon nitride, boron, and pure silicon (e. g., silicene is a graphene-like allotrope of pure silicon). in contrast, silicates exist as either highly ordered or amorphous (more random) three-dimensional lattices. what could explain why there are there no naturally occurring sheets, stacked sheets, cylindrical tubes, or spheres of network covalent atomic solids composed of silicon and oxygen (sio2)? would pure silicate structures make good lubricants or good electrical conductors?