I am working on my first heat transfer design and I have almost all of my data, but I do not know what to do with it. I know the following for the material on each side of a wall: specific heat viscosity thermal conductivity density velocity for the wall in between them I know the following: thickness mean surface area thermal conductivity i understand all about Reynalds, Nusselts, and Prandtl number as well. i also know the temperature that both substances will initially be. i am trying to figure out how long in time it will take to get one substance (nylon in solid pellet form) to drop from 350 F to 100 F. this nylon will be in a tube with an auger inside moving at a slow rate to transport through the system. On the other side of the wall in the tube will be cold water around 40 F that will be circulating in order to draw the heat out of the nylon. if I can figure out the temperature of either side of the wall, I can solve for how long my tube needs to be through lump mass approx method. Here are some values I have if I attempt to solve for the wall temp assuming it is convective heat transfer: For Nylon Cp specific heat capacity 1670 J/kg-K k thermal conductivity 0.25 W/m-K v velocity 1.524 m/hr (rate of auger) p density 560.645 kg/m^3 R resistance 102317.0565 u viscosity ?? it is around for 1E+12 kg/m-s for solids but this gives me a "h" that doesnt make sense when i solve for it using the Nusselt number. so that didnt seem to work so instead i assume it is conductive heat transfer and use the following: k thermal conductivity 0.25 W/m-K x thickness 0.889 m A Surface Area 17.01674016 m^2 R resistance 0.208970694 but again this does not make sense cause i end up getting a temperature on the S.S. wall of less than 41 F when it is next to 350 F, and the water temp on the other side of the wall is 40 F. what gives? and thanx.