6.Gl APPENDIX VI.G DENSITIES OF TYPICAL RADIATOR STRUCTURES Woodcock and Gregory (6.Gl) mention a figure for (mass of radiator)/(radiator area) of 5 kg/m2, and comment that it is "very light!". Cockfield and Killen (6.G2) built and tested a lightweight aluminum radiator using steel-lined tubing. From the specifications of their radiator, the (mass of radiator)/ (radiator area) figure can be calculated at 6.3 kg/m2. Like the proposed external radiator, Cockfield's and Killen's radiator is cylindrical, but their area density figure does not include supporting structure, leak detection equipment, and leakage control systems . It is assumed that these would add 25% to the mass of the radiator, and an aluminum radiator area density is estimated: SAl rad= 8 kg/m2 Cockfield and Killen also state that above 700°F (644°K), aluminum radiators are not adequate. Though the melting point of Al is 930°K, sublimation of alloying elements into vacuum and creep effects in the radiator occur at lower temperatures. If the Cockfield and Killen aluminum radiator were made of steel, it would have area density 23 kg/m 2 . However, the sections could be made thinner because of the stronger material used. Assuming a 35% reduction in cross-sectional area, a steel radiator area density is estimated: 6steel rad 15 kg/m 2
RkJQdWJsaXNoZXIy MTU5NjU0Mg==