MAE 112 PROPULSION FIRST EXAM February 11, 2009 Do all three problems in one-hundred-and-ten minutes. Books, notes and calculators (without wireless communication capability) can be used freely. 1. Consider a liquid-propellant rocket engine where liquid methane plus a kilogram per second of liquid oxygen flows into the combustion chamber at 15 atmospheres of pressure. The stoichiometric amount of liquid methane is injected continuously into the chamber. The liquids, methane and oxygen, are introduced at their boiling points: 111 K and 90 K, respectively. Methane has a heat of vaporization of 510 joules/ gm and its vapor has a specific heat at constant pressure of 2.19 joules / (gm o K). Oxygen has a heat of vaporization of 212.9 joules/ gm and its vapor has a specific heat at constant pressure of 0.920 joules / (gm o K). The specific heat at constant pressure of gaseous products can be approximated as a constant value of 2.00 joules/(gm o K). Throughout the previous property values, “gm” means grams not gram-moles. The gaseous flow through the
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