Optical characterization of a multipoint lean direct injector for gas turbine combustors: velocity and fuel drop size measurements

Original publisher: Cleveland, Ohio : National Aeronautics and Space Administration, Glenn Research Center, [2010] OCLC Number: (OCoLC)713885807 Excerpt: ... At the downstream location, the drops measured are pri-PIV Results marily from the upper half of the lower injector, though there Figures 16 and 17 present PIV results. The field of view is probably contribution from the lower half of the middle used for PIV isolates the center row of injectors. The pre-injector, as well. This location should correspond with an area sented fields are the average of only 250 image pairs, and are downstream of the recirculation zone, where there may be not necessarily a good statistical sampling. However, limiting interaction between adjacent injectors. Many more droplets the number of pairs was convenient for this first attempt at were measured at this downstream location, all with positive PIV in a combusting case, allowing us to consider issues of velocity. timing, using a shutter, and data storage. Figure 16 shows the The contour plots in Figure 15 display the influence of resultant average droplet velocity and RMS fields from PIV drop diameter on axial velocities at the downstream locations for inlet condition M1 at the Y = 0-mm position. For compar-of X = 9-, 12-, and 15-mm. Data represent the L1 case. For ison, the PDI average velocity data from the same region is these positions, only two size bins are used. The top row plotted on the same scale. The range in RMS for PIV is simi-contains the average axial velocities for drops with linear lar to what we encountered for the individual PDI channels. diameters between 0-and 10-µm, non-inclusive. The bottom Using the PIV vector plot ( center image ) we measured a full row portrays the same information for drop sizes in the range spray angle of approximately 80 °, which is consistent with of 10-to 20-µm, inclusive. For each size range, the span of the PDI results. axial velocities decreases with downstream progression, in...