A correction method for spray intensity measurements obtained via phase Doppler interferometry

A phase Doppler interferometer (PDI) was used to measure the intensity (i.e ., the expected number of droplets measured per unit time) of a swirling me thanol spray flame. Gaps observed in the data, which have been previously r eported (McDonell and Samuelsen 1995), correspond to periods where the PDI was inactive. The intensity of the spray as a function of position within t he flame was determined from the distribution of interarrival times (time b etween subsequent droplets entering the probe volume of the PDI), and a sta tistical simulation was developed to correct for the regularly occurring in tervals in which the PDI does not accept data. The duration of this dead ti me was determined to be similar to 5.2 ms for all points in the flame for w hich data were collected, The intensity of the spray varied by over two ord ers of magnitude throughout the name. A statistical model is presented to c orrect for the observed behavior of the PDI, and the good agreement between the simulations and the experimental data indicate that the spray can be a dequately modeled by Poisson processes.