|| THERMAL PROCESS PROGRAMS:
Six programs allow solutions for transient heating or cooling time of any material in any type of load configuration; transient nodal temperatures of slabs; centerline temperature of cylinders; composition, cost & selection of metallurgical prepared protective atmospheres; purging volume requirements; carburized case depth; dewpoint vs. carbon; heat exchanger sizing.
- Compute the transient heating or cooling time of any load configuration in a chamber equipped with or without fan circulation. The load selection can be a slab heated or cooled from 2 sides, slab heated or cooled from one side, solid square or rectangular bars, solid or hollow cylinders, solid or hollow spheres. The time includes convection, radiation, and conduction heat transfer modes during any desired incremental time periods. Recirculated flow at any velocity can be air, argon, carbon dioxide, carbon monoxide, dissociated ammonia, endo-exothermic, helium, hydrogen, methane, nitrogen, 90%N2/10%H2, or steam. The recirculated gas properties computed and displayed include thermal conductivity, viscosity, film temperature, Reynolds & Prandtl numbers, and the convection heat transfer coefficient. Gases can be above or below atmospheric pressure. Plant elevations can be entered, so that the correct atmospheric pressure is computed. Cooling can also be done in a liquid (quenching in water, brine, caustic, or synthetic liquid), with or without agitation to enhance heat transfer to the part.
Physical properties of 22 common metals are programmed, other metals or non-metals can be entered. Density, specific heat and thermal conductivity are accessed during the computation iterations. The program computes the thermal diffusivity and the BIOT number, for analysis of internal/external thermal resistances of the material.
The computed data shows temperatures from the surface to the center for slabs, cylinders & spheres in 7 equal diameter or thickness increments. If a solid square or rectangular bar is selected, the computed data shows temperatures at the center, each face, temperature at the center of the long edge, and extreme corner, and average temperature.
- Composition, costs, and selection of 12 prepared protective heat treating atmospheres; volume required for various furnace designs, dewpoint & % CO2 vs % carbon in steel, carburized case depths, purging requirements and % oxygen left in air for closed chambers.
- This program computes the equilibrium temperature for metallurgical processes to detemine whether the process is oxidizing or reducing to steel. The furnace atmosphere consists of combusted gases with known values of hydrogen, carbon monoxide and carbon dioxide constituents. The moisture content of the gas is computed after the desired dewpoint temperature is entered. Equilibrium oxidizing/reducing temperatures are based on computed ratios of H2O/H2 and CO2/CO.
- Compute transient nodal temperatures of solid bars, slabs or cylinders during heating at a fixed or uncontrolled rate. If a fixed rate is selected, the chamber set point control temperature is increased at a preselected rate until the final set point temperature is reached. If the load is to be heated at an uncontrolled rate, an entry prompts for the temperature difference between the final set point temperature and the initial load temperature. The control set point temperature then remains constant throughout the heating cycle.
The transient nodal temperatures are displayed and are useful to ascertain compliance with governing specifications during the heating cycle.
- This is a comprehensive stand-alone menu-driven program for preliminary estimating shell and tube, and crossflow duct heat exchangers based on thermal design criteria. Six flow arrangements are programmed; counterflow; parallel flow; 1 shell pass, two or more passes; steam or vapor condensers; refrigerant evaporators/coolers and crossflow tube banks in a duct. Select from 59 programmed fluids including 13 gases, steam, water, acetic acid, 3 alcohols, ammonia, aniline, benzene, 2 brine solutions, any concentration of glycol/water, 11 heat transfer fluids, 12 oils, 10 refrigerants, and toluene. Seventeen tube materials are programmed. Other fluids and pipe materials can be entered.
- This is an executable beta version program similar to HEATCOOL, using equations for transient heating & cooling time, based on data in the text "HEAT TRANSFER: A Practical Approach", by Yunus A. Cengel, copyright 1998 by The McGraw-Hill Companies. The equations determine non-dimensional transient temperature distribution in a one-term approximation of the Fourier infinite series using temperature Temp = (T-Tinf / (Ti-Tinf), distance from the center (X = x / L), Biot number (Bi = h L / k), and time (Tau = a t / Lē) as the dimensionless parameters. a is the symbol for thermal diffusivity = heat conducted / heat stored = k / (wt Cp). The one-term approximation is accurate to less than 2% for Tau > 0.2, which is suitable for most transient heating and cooling problems encountered in industrial heating applications. The program offers eight heat transfer coefficient options, including the Nusselt Equation coefficient (Nu = h D / k) which is applicable to heat transfer on several standard shapes-including slabs (1 or 2 sides), flat plates, solid or hollow cylinders, solid or hollow spheres, for both laminar and turbulent flow.