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Unformatted text preview: 11-10 Nuclear Power Chap. 11 17. Estimate the specific impulse Isp for (a) a chemical rocket burning hydrogen and oxygen at a temperature of 4000 K, and (b) a thermal nuclear rocket emitting hydrogen at 3000K. Solution:
(a) The mass of an exhaust water molecule is Me = 2M(lH) + M(160) = 18 u (18 u)(1.661 x 10-27 kgfu) = 2.990 X 10-26 kg. (b) At an exhaust temperature of 3000 K, the hydrogen is in the form of a diatomic molecule H2. The mass of an exhaust hydrogen molecule is Me = 2 x M(lH) = 2(1.0078u)(1.661 X 10-27 kgfu) = 3.347 X 10-27 kg. = 5.61 km/s. A nuclear rocket propulsion system uses an ion drive to accelerate mercury atoms to energiesof 50 keV. Estimate the specific impulse of this drive. Solution: For a 50-keV mercury ion, classicalmechanics may be used. Thus the speed and the specific impulse of a 50-keV mercury ion (A = 200.6 u) is
- Ve= 2E -2(50,000
MHg eV)(1.602 x 10-19 JjeV) -(200.6 u)(1.661 x 10-27 kgju) = 2.19 X 105 m/s = 219 kill/so July 24, 2002 18. ...
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This note was uploaded on 02/01/2010 for the course ECE 4130 taught by Professor Cady during the Spring '06 term at Cornell University (Engineering School).
- Spring '06