Currently, a comprehensive physical description of sprays is not possible, as the involved heat- and mass-transport mechanisms have not yet been understood completely. Therefore, we here show and apply a straightforward Raman evaluation technique which simultaneously probes spatially resolved (i) droplet temperature, (ii) evaporation progress and (iii) entrainment of air into the spray. First, the working principle of the Raman technique and the calibration of the sensor are described. Then, the applicability of the Raman technique is demonstrated showing example measurement results obtained from a superheated water spray. The plausibility of the obtained measurement results is demonstrated comparing them with computations for thermodynamic equilibrium conditions. Information about the droplet temperature, the evaporation progress and the entrainment of air might complement the insights into heat- and mass-transport mechanisms which can already be provided applying other existing optical spray diagnostic techniques.
Abstract. We present an approach to account for sample inhomogeneities as observed in thin powder samples. To test this model a series of transmission measurements on enriched 240 Pu and 242 Pu oxide samples was carried out. These measurements were performed at GELINA, the pulsed, white neutron source at the Institute for Reference Materials and Measurements in Geel. For all samples a mixture of PuO 2 and graphite powder was used. To reduce the influence of the models for Doppler broadening on the extracted resonance parameters, measurements were performed with sample temperatures of approximately 12 K, 77 K and 300 K. To describe the variation in the sample thickness, caused by the particle distribution in a thin powder sample, a Monte Carlo and an analytical description were used in the resonance shape analysis. The values and uncertainties of the extracted resonance parameters are discussed, and suggestion for future measurements are given.
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