Conversion Correction for Evaluating Net Heat Flux into a Liquid Hydrogen Container
In evaluating the normal evaporation rate of hydrogen containers, an allowance must be made for the loss due to the conversion of the liquid from its ortho to para form. This correction is by no means insignificant since losses, due to conversion may range as high as 30% per day for normal (unconverted) liquid hydrogen. Even for a well-converted product, say 90% para, the initial conversion loss is 1/4% per day assuming no catalyst is present in the storage vessel. And, if a catalyst is present, e.g., stainless steel or traces of oxygen, the rate may well be several times greater, thereby generating internal heating of the same magnitude as the influx of heat from the environment. Thus, it is important that the engineer considering the storage of liquid hydrogen evaluate this conversion loss in making his calculations.
KeywordsLiquid Hydrogen Para Content Internal Heating Calculated Heat Heat Leak
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