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Difficult Heat transfer problem

  1. Aug 17, 2007 #1
    We are compounds of peroxide cure insulation materials and often get asked by customers on recommendations for processing conditions and more often then not our answers is the very not commital "It depends".

    Lots of factors are needed to be taken into consideration when processing our material in Continuous Vulcanization lines or CVs. The first is the material it self, the conducter (size, type and temperature), insulation wall thickness, steam temperature, steam leg length, cooling water lenth, type of peroxide, compound extrusion temperature and finally the line speed.

    Given that most of the variable are know is there a way to model they system to come up with and equation that best approximates the process to allow us to advise the customer on how the materials should be run? Today most compounds are processed by trial and error. We have a general idea based on past history where to start but we are interested in getting at a model to better advise the customer.


    Insulation I: Know wall thickness (r2-r1), known heat capacity (ki), known extrusion temperature Ti

    Conductor C: Known conductor radious (r1), know heat capacity (kc), known initial temperature Tc

    Steam Leg: Known steam Temperature (Ts), known steam tube length (Ls), Known hsteam = 32,250 W/(m^2*K)

    Water Leg: Known water Temperature (Tw), known water leg Length (Lw)

    It is commonly accepted that "Full cure" is considered 87% or 3 half lives.

    Known half life at Ts.

    Unknowns: Time to heat the inside of the cable to adequate T to ensure full cure (3 halflives) by the time it reaches the end of the steam leg.

    Recommended line speeds.

    I know its very complex so any input would be appreciated.


  2. jcsd
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