F.2 Bauer "Specific Enthalpy for Different Water Releases" This is an elementary thermodynamic analysis to compare the specific enthalpy and effective temperature for Highwater (Lundquist, 1962), LAGOPEDO, and various HLLV and POTV burns of hydrogen-oxygen engines. The conclusion is that these water injections correspond to a very wide range of effective enthalpies or temperatures. Highwater. One may assume that the material was injected as liquid water at approximately 15°C, at apogee of the carrier rocket so that no kinetic energy was contributed due to the motion of the rocket. Relative to ice at 0 K the enthalpy of injected material was 0.12 Kcal/gm (see JANAF Thermochemical Tables, Report NSRDS-NBS 37, 2nd Ed., 1971, discussion on ^0). LAGOPEDO. The water is produced by combustion of high explosives near the apogee of a sounding rocket. The combustion temperature may be taken as 2500 K so that the enthalpy (relative to ice at OK) is 2.13 Kcal/gm. H2-O2 Rocket Engine Burns. We assume that the exhaust is 70% ^0, 30% H2, so that the effective molecular weight is 13.2. The limiting exhaust velocity in vacuum is taken to be 4.5 km/sec (see Section 3.1.3,B) corresponding to an enthalpy of 31.9 Kcal/mol relative to ice at 0 K, or to a combustion temperature of 2950 K. However, because of the motion of the vehicle the enthalpy of the actual burns is quite different. Thus for the HLLV second stage burn shown in Fig. 1, in intervals 11 to 13 the vehicle speed ranges from 4.4 to 6.9 km/sec, so that the actual enthalpy of exhaust gas ranges from 0 up to 9.1 Kcal/mol, or the temperature may be as high as 1050 K. For the HLLV circularization and deorbit burns the effective velocity of 7.6 km/sec (circular orbit velocity) less 4.5 km/sec, giving a net velocity of 3.1 km/sec, an enthalpy of 15.2 Kcal/mol, corresponding to 1600 K. For the POTV burns (see Table 8) the absolute exhaust velocity ranges from 2.15 to 13.3 km/sec, enthalpies lie in the range 7.3 to 280 Kcal/mol, corresponding to temperatures from 850 K to above 10,000 K.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==