scholarly journals Comparing Alternative Jet Fuel Dependencies Between Combustors of Different Size and Mixing Approaches

2021 ◽  
Vol 9 ◽  
Author(s):  
Randall C. Boehm ◽  
Jennifer G. Colborn ◽  
Joshua S. Heyne

Analyses used to reveal fuel dependencies on lean blow out and ignition at specific operating conditions in specific combustors show inconsistent trends with each other. Such variety is however consistent with the occurrence of transitions between the governing physical phenomena as the ratios between evaporation, mixing, or chemical time scales with their respective residence times also vary with specific operating conditions and combustor geometry. It is demonstrated here that the fuel dependencies on LBO in a large, single-cup, swirl-stabilized, rich-quench-lean combustor varies with operating conditions such that a feature importance match is attained to fuel dependencies observed in a much smaller combustor at one end of the tested range, while a qualitative match to fuel dependencies observed in a lean, premixed, swirler-stabilized combustor of comparable size at the other end of the tested range. The same reference combustor, when tested at cold conditions, is shown to exhibit similar fuel dependencies on ignition performance as the much smaller combustor, when tested at both cold and warm conditions. The practical significance of these findings is that a reference rig, such as the Referee Rig, can capture fuel performance trends of proprietary industry combustors by tailoring the inlet air and fuel temperatures of the tests. It is, therefore, a trustworthy surrogate for screening and evaluating sustainable aviation fuel candidates, reducing the dependency on proprietary industrial combustors for this purpose, thereby increasing transparency within the evaluation process while also expediting the process and reducing cost and fuel volume.

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1948
Author(s):  
Zhibin Yang ◽  
Robert Stachler ◽  
Joshua S. Heyne

The approval and evaluation process for sustainable aviation fuels (SAF) via ASTM D4054 is both cost- and volume-intensive, namely due to engine operability testing under severe conditions. Engine operability tests of combustor under figures of merit (FOM) limit phenomena are the fuel effects on lean blowout, high-altitude relight, and cold-start ignition. One method to increase confidence and reduce volume in tiered testing is to use surrogate fuels for manipulation of properties. Key fuel performance properties (surface tension, viscosity, density) for cold-start ignition was determined prior to this study. Prior work regarding this FOM has not considered the combination of these properties. A surface tension blending rule was validated and incorporated into the jet fuel blend optimizer (JudO). A generalized surrogate calculator for N-dimensional surrogate components and features was developed. Jet fuel surrogates developed in this study were a mixture of conventional and sustainable aviation fuels instead of pure components. These surrogates suggested to be tested in this study could illuminate near worst-case effects for sustainable aviation fuel in a given configuration/rig. With those scenarios tested, we can further understand the influence on the key properties relative to cold-start ignition. This work and supporting experimental evidence could potentially lower the barrier for SAF approval processes.


2021 ◽  
Vol 1 (1) ◽  
pp. 68-80
Author(s):  
Adam Dziomdziora ◽  
Przemysław Ignaciuk

The paper analyzes the formation of the bullwhip effect in logistic systems as a significant threat to preserving stability in the face of non-negligible goods transport delay and uncertainty of demand and stock records. The popular order-up-to policy is selected as the method governing the goods flow. A dynamic model of entity interaction is constructed and examined, first, analytically, then in numerical tests for various scenarios of practical significance, e.g., a supply chain with external and local demand signals or real-world European goods distribution system. It has been found that the order-up-to policy does not trigger the bullwhip effect despite the delays in the goods delivery in the nominal operating conditions in supply chains. However, in networked environments, even the basic configuration triggers the bullwhip effect.


2021 ◽  
Vol 75 (4) ◽  
pp. 3-12
Author(s):  
Zayats Yuriy Aleksandrovich ◽  
◽  
Zayats Tatiana Mikhailovna ◽  
Savelyev Maksim Anatolevich ◽  
◽  
...  

Logistics support of products at all stages of the life cycle is gaining increasing influence. This is facilitated by the increasing complexity of structures, a large number of elements, the intro-duction of mechatronic systems. Under these conditions, the relevance of developing methods for analyzing the design of samples increases. The developed model for analyzing the diesel cooling system is based on the principles of cognitive modeling. The practical significance of cognitive models is shown, which consists in the possibility of predicting changes in the influence of system elements on the target function in various operating conditions.


ACS Omega ◽  
2019 ◽  
Vol 4 (5) ◽  
pp. 8255-8273 ◽  
Author(s):  
Igor Velkavrh ◽  
Ion Palamarciuc ◽  
Dan Gelu Galuşcă ◽  
Alexander Diem ◽  
Josef Brenner ◽  
...  

Author(s):  
Andrew Corber ◽  
Nader Rizk ◽  
Wajid Ali Chishty

The National Jet Fuel Combustion Program (NJFCP) is an initiative, currently being led by the Office of Environment & Energy at the FAA, to streamline the ASTM jet fuels certification process for alternative aviation fuels. In order to accomplish this objective, the program has identified specific applied research tasks in several areas. The National Research Council of Canada (NRC) is contributing to the NJFCP in the areas of sprays and atomization and high altitude engine performance. This paper describes work pertaining to atomization tests using a reference injection system. The work involves characterization of the injection nozzle, comparison of sprays and atomization quality of various conventional and alternative fuels, as well as use of the experimental data to validate spray correlations. The paper also briefly explores the application viability of a new spray diagnostic system that has potential to reduce test time in characterizing sprays. Measurements were made from ambient up to 10 bar pressures in NRC’s High Pressure Spray Facility using optical diagnostics including laser diffraction, phase Doppler anemometry (PDA), LIF/Mie Imaging and laser sheet imaging to assess differences in the atomization characteristics of the test fuels. A total of nine test fluids including six NJFCP fuels and three calibration fluids were used. The experimental data was then used to validate semi-empirical models, developed through years of experience by engine OEMs and modified under NJFCP, for predicting droplet size and distribution. The work offers effective tools for developing advanced fuel injectors, and generating data that can be used to significantly enhance multi-dimensional combustor simulation capabilities.


2021 ◽  
Vol 8 ◽  
pp. 122-135
Author(s):  
P.V. Pustozerov ◽  
A.L. Priorov

Problem statement. With the development of devices for electronic control of the spatial position of the antenna radiation pattern, it became possible to control the time and duration of probing the radar station of various angular directions. There are many works based on the use of this principle to solve various radar tasks, in particular, to implement the target tracking mode. However, there is no general overview of the developed methods for controlling the parameters of the maintenance mode, the conditions and restrictions introduced in them, control and optimization criteria, as well as the scope of application. Goal. Analysis of the main methods of controlling the parameters of the tracking mode of a multifunctional radar station, including the control criteria used. Results. The analysis of the main methods of controlling the time of probing a target by a radar station, the duration of its probing pulses and signal is carried out. All methods are combined into several groups, the conditions and restrictions introduced during their development are defined. The quality criteria on the basis of which they are synthesized are analyzed. Practical approaches to calculating the parameters of the tracking mode of modern multifunctional radar stations are considered. The directions of further research of the subject area under consideration are formulated. Practical significance. The scientific and methodological apparatus used in calculating the parameters of the tracking mode of multifunctional radar stations is determined. Mathematical equations are given for calculating the duration of the probing signal and the time of probing the target. A set of parameters that must be taken into account when synthesizing control methods is determined. The applicability of the methods in various operating conditions of the radar station is evaluated.


Sign in / Sign up

Export Citation Format

Share Document