Flaring geometry

Flow Nozzles A simple form of flow nozzle is shown in Fig. 10-17. It consists essentially of a short cylinder with a flared approach section. The approach cross section is preferably elliptical in shape but may be conical. Recommended contours for long-radius flow nozzles are given in ASME PTC, op. cit., p. 13. In general, the length of the straight portion of the throat is about one-h f throat diameter, the upstream pressure tap is located about one pipe diameter from the nozzle inlet face, and the downstream pressure tap about one-half pipe diameter from the inlet face. For subsonic flow, the pressures at points 2 and 3 will be practically identical. If a conical inlet is preferred, the inlet and throat geometry specified for a Herschel-type venturi meter can be used, omitting the expansion section. 

The value of W calculated from the gas composition or from Equation 5 should be considered to be a minimum requirement. A multijet flare should be designed with a calculated air capacity as high as possible, as limited by practical limitations of economics and geometry. 

The thermal structure of the disks plays a central role in determining the chemistry and the observable spectrum. The thermal structure, in turn, is set by the disk geometry and accretion rate, an important heat source. As a function of these parameters the mid-plane temperature of the disk can vary between the mild T r 1//2 for a flared disk to the rapidly declining of T r 3/4 for a flat disk. The highest temperatures in the static disk are reached at its innermost edge, directly exposed to the star. 

The temperature distribution is not only a function of radius, but also depends on the stellar luminosity, the disk geometry, and may depend on the accretion rate (see Table 8.1 and Section 3.3) for example, at a given radius irradiated flared disks will be warmer than flat disks. Naturally, hotter stars will heat their disks to higher temperatures at a given radius thus, mid-infrared spectroscopy probes different radii in different disks. 

There are several abatement techniques commonly used to reduce the gas jet noise emitted from flares. Several of these techniques include mufflers, water injection, and modificahons to the nozzle geometry. Mufflers are mosf commonly used on sfeam-assisted flares to abate the high-pressure steam jet noise as shown in the illustration in Figure 8.29. 

Measurement of fhe crossflow flame geometry is necessary to the understanding of fhe extent of flare dispersion, radiative heaf fransfer to fhe surroundings, and... 

This chapter presents the experimental modeling of flares as turbulent diffusion flames in crossflow. We have reviewed the parameters that affect the flare performance in the field. Experimenfal facilities and insfru-mentation employed for model sfudies are presented. A summary of existing data on flame appearance, geometry, radiation, and stability has been included. Data on inflame temperature, velocity, and species concentration fields have also been discussed. Field fesf dafa are to be used in conjunction with laboratory model data to validate the results and derive scaling relations. 

Other variants of the standard Venturi geometry include the Dali mbe, Venturi nozzle, and Tuyere (or simply flow nozzle). The Venturi nozzle lacks the converging inlet but retains the flared outlet. A Tuyere (or simply flow nozzle) is an extreme variant of a Venturi in that it is essentially only the throat section— the converging and diverging sections are absent. It resembles an orifice because... 

FIGURE 29.6 Schematic illustration of neck-down and flare-out geometries for growing dislocation-free crystals. 

The mass consumption rate will also affect the general particle concentration in the plume and thus directly influence the optical thickness with any given flare candle geometry. The optical thickness is given by... 

The radiant intensity profile for equal amounts of standard MTV decoy flare mix with the above composition is depicted in Figure 10.23. The spectral efficiency for the latter is about twice ( 2.03) in the 2-2.6 pm band. This is due to the much higher Mg content in MTTP formulation (66 vs 54wt% Mg). However, despite the high Mg content, the latter formulation shows a very slow rise in intensity, indicating a slower burn rate. Thus this material would require a different grain geometry to meet with operational rise time specifications. 

Figure 10.24 shows a cross-geometry flare grain with applied first fire manufactured from the above-mentioned composition. 

The grain in its final geometry is applied with both intermediate and first fire to facilitate ignition transfer and ignition of the pellet. Figure 18.20 depicts a cross section of a 1 x 1 in. flare grain with applied intermediate fire based on MTV slurry. Figure 18.21 depicts ram-extruded cruciform 1 x 1 in. pellet with both first and intermediate fire applied [24]. 

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