2000Many combustion systems inject air into a hot fuel-nch cross-flow to minimize carbon monoxide and unbumed hydrocarbon emissions. Exemples hclude staged air injection in fluidized bed cornbustors, gas turbine engines, and electric arc fÙmace exhaust aflerbumers. Low CO and m b w t hydrocarbon emissions are important design objectives. Efforts in modehg combustion have fded in accurately predicting the levels of these emissions. The xnain aim of this study is to irnprove our understanding of the relationship between mixing, chernical kinetics, and combustion &ciency for air jets in a hot reacting cross-flow.Carbon monoxide and hydrogen concentration measurernents have k e n made for six different round jet configurations issuing air into a hot reacting cross-flow. The study of the performance of four different 9 round jets modules having diffêrent jet diameters indicated that the overall equivalence ratio bas a significant effect on the maximum combustion &ciency. An equivalence ratio of approxbateiy 0.8 leads to the best combustion efficiency for all of the 9 round jet modules. This result is similar to what is observeci in premixed combustion. The predominance of the S i of the equivalence ratio suggests that some premixing between the jets and the cross-flow takes place prior ii to combustion. The rest of the d e n t s weze run such that the optimum mixing 4-24List of Tables Table 3- The mean value of the total cacbOn concentration at x/D=1.5
This work is an experimental investigation of the flow downstream of a low emission nozzle. The nozzle is a 3×3 square matrix of nine small swirling air jets, has a design swirl number of 0.8, and operates at a Reynolds number of 40,000. Particle image velocimetry (PIV) was used to map the velocity field under nonburning and atmospheric conditions for the first 18 jet diameters downstream of the nozzle exit plane. Seeding was liquid injected into the air stream and drops were sized to filter out those larger than 3×3pixels. The results showed that the cluster blends into a single jet-like flow 12 jet diameters downstream with the axial component of the velocity displaying self-similar properties. Lateral jet interaction slows the decay of the axial component of the velocity and jet expansion in the developed region while accelerating the decay of the radial component.
This work examines the flow downstream of a Parker Hannifin low NOx LDI nozzle. The nozzle is a square matrix of 3 × 3 airblast simplex fuel ports. The air pressure drop was set to 5%, for a Reynolds number of 40,000. Liquid injection pressure was 2.28kPa. The nozzle is tested at atmospheric conditions without combustion. The objective of this work is twofold: first characterize the spray and the turbulent flow fields; and second examine the effect of the interaction between jets on turbulence and spray profiles. Jet-jet lateral impingement starts within ∼ 1–2 nozzle diameters downstream. The comparison of a single jet and the 3 × 3 matrix spray profiles shows some degree of coalescence due to the interaction between jets. Despite this, the Sauter mean diameter of the resulting spray field is in the 25–35 μm range. In the first few air swirl cup diameters downstream of the nozzle exit plane (down to z/D = 3), the droplets are still accelerating to the air velocity and turbulence is anisotropic. No–slip and turbulence isotropy assumption are accurate only well downstream of the exit plane (z/D = 7.5).
Achieving rapid mixing is the main challenge to reducing NOx levels in non-premixed liquid fired gas turbine combustors. Multipoint lean direct injection (LDI) is among the techniques used to achieve low emissions and good mixing by injecting fuel in small amounts through different injection ports. This study looks at the flow characteristics of a nozzle using this concept. The Parker Hannifin injector used is a square matrix of nine simplex fuel nozzles. Phase Doppler particle analyzer was used to measure both the spray characteristics as well as the gaseous phase turbulence flow field. The average velocities, Reynolds stresses and the Sauter Mean Diameter were measured at a series of positions downstream of the nozzle exit, x3, ranging from 0.6 to 7 times the swirl cup diameters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.