Wall heat flux measurements in a 1.5 in. diameter circular cross-section rocket chamber for a uni-element shear coaxial injector element operating on gaseous oxygen (GOz)/gaseous hydrogen (GH,) propellants are presented. The wall heat flux measurements were made using arrays of Gardon type heat flux gauges and coaxial thermocouple instrumentation. Wall heat flux measurements were made for two cases. For the first case, GOZ/GHz oxidizer-rich (O/F=l65) and fuel-rich preburners (O/F=1.09) integrated with the main chamber were utilized to provide vitiated hot fuel and oxidizer to the study shear coaxial injector element. For the second case, the preburners were removed and ambient temperature gaseous oxygen/gaseous hydrogen propellants were supplied to the study injector. Experiments were conducted at four chamber pressures of 750, 600, 450 and 300psia for each case. The overall mixture ratio for the preburner case was 6.6, whereas for the ambient propellant case, the mixture ratio was 6.0. Total propellant flow was nominally 0.27-0.29 Ibm/s for the 750 psia case with flowrates scaled down linearly for lower chamber pressures. The axial heat flux profile results for both the preburner and ambient propellant cases show peak heat flux levels at axial locations between 2.0 and 3.0 in. from the injector face. The maximum heat flux level was about two times greater for the preburner case. This is attributed to the higher injector fuel-to-oxidizer momentum flux ratio that promotes mixing and higher initial propellant temperature for the preburner case which results in a shorter reaction zone. The axial heat flux profiles were also scaled with respect to the chamber pressure to the power 0.8. The results at the four chamber pressures for both cases collapsed to a single profile indicating that at least to first approximation, the basic fluid dynamic structures in the flow field are pressure independent as long as the chamberhnjectorhozzle geometry and injection velocities remain the same.Graduate Student, Student Member AIAA.: Research Associate, Member AIAA.
There has been considerable research on the prevalence and demographic profile of cancer patients who opt to supplement conventional therapies with the use of complementary therapy. There is rather less information on the personality and adjustment variables associated with the decision to use complementary therapy. The aim of the present study is to investigate the relationship between the use of complementary therapies by cancer patients and their mental adjustment to cancer, recovery locus of control, life orientation and psychopathology. Two groups were drawn from a regional centre which provides both conventional and complementary cancer treatments. Participants in Group 1 (n = 61) opted for complementary therapies in addition to conventional treatments for cancer, while participants in Group 2 (n = 56), chose conventional treatment only. All participants completed the Mental Adjustment to Cancer Scale (MAC), the Recovery Locus of Control Scale (RLOC), the life orientation test (LOT), and the Hospital Anxiety and Depression Scale (HADS). Information regarding demographic details and patients' motivation for the use of complementary therapy was also collected. Those people who chose complementary therapy demonstrated a mental adjustment to cancer which is characterised by significantly higher levels of fighting spirit and anxious preoccupation. This group had also a higher internal recovery locus of control than those receiving conventional treatment alone. There were no significant differences between the groups on life orientation or psychopathology. The findings of this study do not support the argument that the use of complementary therapy is associated with higher levels of psychopathology and distress. However, the data do indicate that for some patients the use of complementary therapy fulfils an important psychological need. The finding that psychosocial variables like fighting spirit and locus of control may impact on an individual's therapeutic choice can assist clinicians in tailoring interventions to personality and adjustment characteristics.
The results from a series of detonation experiments conducted to characterize the deflagration-to-detonation transition (DDT) process for ethylene-air mixtures in a 44-mm-square, 1.65-m-long tube are described. Experiments were conducted for both single-shot detonations involving quiescent mixtures as well as multicycle detonations involving dynamic fill. For the experiments, high-frequency pressure and flame emission measurements were made to obtain the compression wave and flame speeds, respectively. In addition, schlieren and hydroxyl-radical/planarlaser-induced-fluorescence (OH-PLIF) imaging were applied to investigate the interactions between the shock-wave and combustion phenomena during both deflagration and detonation. For ethylene-air mixtures, strategically placed obstacles were necessary to achieve DDT. The effect of the presence of obstacles on flame acceleration was systematically investigated by changing the obstacle configuration. The parametric study of obstacle blockage ratio, spacing between obstacles, and length of the obstacle configuration indicated that for successful detonations the obstacle needs to accelerate the flame to a minimum flame speed of roughly half the Chapman-Jouguet detonation velocity. Differences in the flame and compression wave velocities demonstrated the development of a coupled feedback mechanism as the wave propagated along the tube. A series of simultaneous schlieren and OH-PLIF images showed that the obstacle plays a major role in generating small/large-scale turbulence that enhances flame acceleration. Localized explosions of pockets of unburned mixture further enhanced the shock-wave strength to continuously increase the flame speed. The results of this experimental study support the importance of obstacles as a means to enhance DDT and provide a potential solution for practical pulse-detonation-engine applications.
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