Conference proceeding
Spray Characteristics of a Hybrid Airblast Pressure-Swirl Atomizer at Cold Start Conditions using Phase Doppler Anemometry
Triennial International Conference on Liquid Atomization and Spray Systems, 14 (Chicago, Illinois, 07/22/2018–07/26/2018)
2018
Handle:
https://hdl.handle.net/2376/117696
Appears in Aviation Sustainability Center (ASCENT)
Abstract
There has been an increased interest in alternative avaiation fuels to reduce pollutant emissions to mitigate climate change and diversify the fuel. The presented work examines the spray characteristics of two aviation fuels and one fuel candidate as part of a larger effort by the National Jet Fuel Combustion Program (NJFCP). A hybrid airblast pressure-swirl atomizer was used to investigate the spray characteristics of Jet-A (A-2), JP-5 (A-3), and a JP-5/farnesane blend (C-3) at cold start conditions: ambient gas pressure Pvessel = 1.01 bar, fuel temperature Tfuel = 239 K, and atomizing gas temperature Tgas = 239 K. The pressure drop across the swirler of the atomizer (∆P/P) was varied in order to investigate the effect on the spray characteristics. Phase Doppler anemometry (PDA) was used to measure the drop size and drop velocity of the spray at multiple axial locations downstream of the swirler exit plane. The spray was measured as far as 30 mm from the centerline of the spray in 5 mm increments and in both radial directions. The D10, D32, and MMD were used as representative diameters to characterize the mean drop size. The mean axial drop velocity with its root-mean square was used to characterize drop velocity. The investigation showed the D10, D32, and MMD decreased with increases in ∆P/P for all fuels. It was observed that no significant variations occured among the test fuels in D32, MMD, and Uz comparisons. Spray measurements at cold start conditions were compared with the measurements from a previous investigation at lean blowout(LBO) conditions. Introduction Fuels derived from sources alternative to petroleum are of interest to the aviation industry. Alternative fuels diversify the energy supply, provide low-cost fuel alternatives, and mitigate climate change [1][2]. Current research efforts in this area are focused on drop-in fuels that can be integrated into existing infrastructure and gas turbine engines without requiring significant modification. These fuels must perform to the same standards as fuels currently used in industry to avoid degradation in the margins of safety, operability, performance, and durability[2]. The requirements for the commercial use of alternative fuels has resulted in an extensive certification process outlined in ASTM D4054[2]. Atomization is an important aspect of the combustion process in gas turbine engines and is one of the physical processes evaluated when considering alternative aviation fuels for commercial use due to its effects on combustion efficiency and pollutant emissions[3][5]. The temperature of the fuel is considered for alternative fuels undergoing certification, because the physical properties of the fuel such as liquid viscosity and liquid-gas surface tension vary with temperature. Liquid-gas surface tension and liquid viscosity values increase as temperature decreases. Rizkalla and Lefebvre [4] showed that increases in surface tension and viscosity of the fuel produced larger mean diameter sizes. Wang and Lefebvre [6] demonstrated that increasing fuel temperature resulted in smaller mean drop sizes. The fuel Sasol FSJF was the first alternative jet fuel approved for commercial use after it underwent extensive testing including at cold start conditions[7]. The representative diameter that was used to characterize the spray is the Sauter mean diameter(D32). The D32 is a fifth order mean that represents the ratio of drop volume to drop surface area. It is a diameter characteristic commonly used for comparisons in mass transfer and reaction applications such as gas turbine engines[3][8].
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Details
- Title
- Spray Characteristics of a Hybrid Airblast Pressure-Swirl Atomizer at Cold Start Conditions using Phase Doppler Anemometry
- Creators
- Andrew J. Bokhart (Author) - Purdue University West LafayetteDongyun Shin (Author) - Purdue University West LafayetteNeil S. Rodrigues (Author) - Purdue University West LafayettePaul E. Sojka (Author) - Purdue University West LafayetteJay P. Gore (Author) - Purdue University West LafayetteRobert P. Lucht (Author) - Purdue University West Lafayette
- Conference
- Triennial International Conference on Liquid Atomization and Spray Systems, 14 (Chicago, Illinois, 07/22/2018–07/26/2018)
- Academic Unit
- Aviation Sustainability Center (ASCENT); Alternative Jet Fuel
- Grants
- 13-C-AJFE-PU-005, Federal Aviation Administration (United States, Washington) - FAA
- Identifiers
- 99900581260201842
- Language
- English
- Resource Type
- Conference proceeding