Speed measuring method

摘要

In a method or a device for contactless measurement of speeds, speed distributions and decomposition (decay) frequencies in liquid jets and flames, two light beams of an intensive light source are focussed in the measurement volume of a layer of liquid or flame in such a way that it is possible to use two light-sensitive detectors to measure the transmission of the light in the case of a focal distance of DELTA s in the measurement volume. The temporal shift of DELTA t in the transmission curves is used, with v = DELTA s/ DELTA t to obtain speeds and speed distributions in injection jets and flames. Furthermore, the temporally detected transmission curve can be used for the purpose of conducting frequency analysis investigations with the aid of digital Fourier analysis (FFT analysis). The wavelength lambda which determines the globe magnitude in liquid jets and flames can be determined using the wave equation lambda = v.f from the speed v or the temporal variation in the speed in the layer of a liquid or a flame as well as from the frequencies f which have been determined from the frequency spectrum. <IMAGE>