RFI Aero-Spray Fuel Injector Updated Timeline.pdf

80GRC021RFI0005 – Request for Information (RFI) Aero-Spray Fuel Injector

NASA GLENN RESEARCH CENTER (GRC) IS HEREBY SOLICITING INFORMATION

FROM THE INDUSTRY FOR THE AERO-SPRAY WORKING GROUP

No solicitation exists; therefore, do not request a copy of the solicitation. If a solicitation is released, it will be synopsized on SAM.gov. Interested firms are responsible for monitoring this website for the release of any solicitation or synopsis.

I. Background

The Aero-Spray Working Group was formed in 2020 to develop a program that provides a detailed database of aero-engine liquid injection and atomization characteristics internal to the fuel nozzle and very near the fuel nozzle exit. The proposed program will conduct x-ray measurements and high fidelity, first principle simulations that ultimately lead to improved reduced-order spray modeling tools. The development of such a unique liquid atomization database addresses combustion modeling goals in NASA’s Transformational Tools and Technologies project. The Working Group includes participation from NASA, Argonne National Laboratory (Argonne), Air Force Research Laboratory, Office of Naval Research, GE Aviation, GE Research, Pratt & Whitney, Raytheon Technologies Research Center, Rolls-Royce and Honeywell. A key element of the proposed program is the design and fabrication of a non-proprietary fuel injector that includes several liquid atomization techniques and permits high-quality x-ray measurements.

The Aero-Spray Working Group program is planning to conduct three test campaigns with different ranges of air pressure and temperature representing combustor inlet conditions: (1) 1 atm pressure and room temperature air; (2) pressures up to 50 atm and room temperature air; (3) pressures up to 50 atm and temperatures up to 1300 F. The tests will be conducted in Argonne’s Advanced Photon Source (APS) facility (specifically the 7-BM beamline). The Working Group has developed a draft fuel injector design and performed preliminary computational fluid dynamic (CFD) simulations of the design to confirm aerodynamic characteristics. Also, Argonne has performed tests with an existing jet-in-crossflow rig at atmospheric conditions to assess the impact of x-ray absorption through different materials and material thickness on the spatial and temporal resolution of x-ray diagnostics to be used in future Aero-Spray program test campaigns.

II. Aero-Spray Fuel Injector Material and Performance Requirements

The Fuel Injector has been conceptualized by the Aero-Spray Working Group to include industry-relevant atomization physics for investigation. Namely, a primary liquid circuit supplying a pressure-swirl atomizer, a secondary liquid circuit supplying jets in crossflow, and an optional third fuel circuit between air swirler flow paths which forms a film at the exit of the wall between the two swirlers to study air-blast (shear) atomization.

The air flow is supplied through axial swirlers with an effective flow area of 0.33 in2 as the baseline sizing for the injector (see figures below). The jets in crossflow liquid flow is intended to interact with the swirling air flow and to form a liquid film along a confining wall. The pressure-swirl atomizer liquid flow interacts with swirling air flow and may under some conditions interact with the liquid film downstream of the injector exit. The air-blast circuit could be included as an optional addition as part of a modular injector design. Each of the three modes of atomization (or fuel circuits) may be studied independently or together. These physical processes are expected to be observable via high-speed x-ray imaging due to the material choices for the confinement walls.

Based on the desired observable physics, the following is a list of prioritized design requirements for the Fuel Injector:

1. Allow for the ability to x-ray image internal multi-phase physics: jet-in-crossflow, pressure-swirl sheet spray, wall impingement, filming, and shear atomization.

This requires the use of wall materials in the regions of interest that are optimized for x-ray transparency while meeting conditional operability. This also requires a limitation in the number of liquid jets (maximum of four) such that the flows are not confounded when viewed in projection.

2. Provide a swirling air flow with high azimuthal uniformity at the location of liquid introduction. This has been conceived with the use of helical axial swirlers.

3. Produce a realistic atomization behavior. Downstream spray spread and droplet diameters should be within an industry-relevant range, as produced by the primary (pressure-swirl) and secondary (jets-in-crossflow) liquid circuits. Secondary jets are expected to impinge on the inner confinement wall and produce a film, and the primary sheet is expected to interact with the secondary flow as it shears from the filming surface.

4. Meet above requirements 1-3 for liquid injection of Jet-A fuel, or calibration fluid (e.g. MIL-PRF-7204F Type II), and remain compatible with water for shakedown testing, into air pressures of 1-50 atm and air temperatures 70-1300 F. Ideally, a single design would meet these requirements, but options that include multiple designs or modular designs to address different operating conditions and modes of atomization are also of interest.

These priorities illustrate the need for x-ray access to the relevant physics. Also, the Fuel Injector is not expected to meet traditional requirements for flame stabilization, as reacting flow is outside the scope of the program. Tolerances for design specifications are relaxed relative to high-performance standards to permit a non-proprietary design.

Material selection for the air flow confinement walls surrounding the region of interest is an open parameter. The primary requirement for the Fuel Injector is to observe the multi-phase physics with x-ray imaging. This influences the choice of wall material, in the region of interest, to reduce the mass attenuation coefficient of x-rays (considered at 15 keV), reduce the material density, reduce the wall thicknesses, while maintaining structural composition for the operating conditions of interest. The following table lists material options that have been considered, though, is not comprehensive to the material options for production:

Material mass attenuation coefficient, 15 keV, cm2/g (minimize)

Density, g/cm3 (minimize)

Melting point, °F

Polymer/acrylic 1.1 1.18 320 Beryllium 0.31 1.85 2350 Aluminum 7.96 2.7 1221 Titanium 35.9 4.5 3034 Nickel 70.8 8.9 2647

A desired modular design allowing for separable components, explained below, can also facilitate a choice of fabricating multiple wall sets, to meet design and fabrication constraints.

There are no constraints on the material selection for the inner liquid nozzle hardware for x-ray compatibility.

The Fuel Injector has been sized comparably to industry hardware and will operate at industry-relevant conditions. Basic design specifications for the liquid and air flows, as well as the overall envelope are listed as follows:

Design Parameter Target Tolerance Primary Circuit FN 1.5 +/- 5 % Primary Circuit Spray Angle

50 +/- 5 deg at 1” downstream

SMD (1atm, quiescent) 30 +/- 10 Secondary Circuit Orifice Count

Secondary Circuit Orifice Size

0.020” +/- 0.001

Secondary Orifice Drill Angle

45 deg +/- 2 deg

Inner Air Swirl Vanes 8x, Clockwise viewing from upstream, 45 deg

Outer Air Swirl Vanes 8x, Counter-clockwise viewing from upstream, 45 deg

Inner Air Effective Area 0.198 in2 (0.33 * 60%) +/- 5% Outer Air Effective Area 0.132 in2 (0.33 * 40%) +/- 5% Maximum Diameter (envelope)

( 1.34”, current), 3” dump plane diameter

Flexible tolerance, more strict on wall thicknesses

With the design requirements and geometry specifications, a concept geometry was produced to perform initial aerodynamic flow simulations. Large eddy simulation computations provided desirable flow splits and air swirl uniformity at the region of liquid introduction. This concept design should serve as a starting point for detailed design. The geometry and simulation results are publically available for download at <https://anl.box.com/s/j7smjkjv8cb0t160v408jdcrgkd5viu8>.

a. Simplified concept

b. Detailed concept used for CFD investigation

This Fuel Injector will be designed to fit into a bulkhead that is contained in a 3 in.

diameter chamber. Chamber design may be matured concurrently with the detailed design of the Fuel Injector.

To improve future study flexibility, it is desired for the central liquid nozzle hardware to be separable from the external swirler set hardware such that either could be redesigned and replaced.

Rotational indexing of the central liquid nozzle hardware to the swirler and the external bulkhead is desired for measurement repeatability to geometric features.

III. Request for Information

For the purposes of this RFI, the Aero-Spray Working Group seeks information on design options and fabrication feasibility and costs of non-proprietary fuel injectors that meet the requirements described in Section II. The responses should include the following:

a) Your interest and capabilities to design and fabricate non-proprietary fuel injector(s) meeting the requirements of the Aero- Spray Working Group.

b) A rough estimate of cost and schedule to fabricate non-proprietary fuel injector(s) meeting the requirements of the Aero-Spray Working Group

c) Identify any aspects of the design that would be proprietary. Please recognize that the goal and intent of the Aero-Spray Working Group is the design and fabrication of a fuel injector(s) that contain no proprietary designs or components.

d) Indicate the combination of materials and interchangeable parts expected for a proposed design used to generate the cost estimate

IV. RESPONSES

a) Interested parties are requested to respond to the information requested in Section III.

b) Questions regarding this announcement shall be submitted in writing by e-mail to the Contracting Officer, Ian Park at ian.park@nasa.gov no later than 3:00pm ET on August 4, 2021.

c) All responses shall be submitted electronically via email to Ian Park at ian.park@nasa.gov no later than 4:00 ET, July 19 2021.

Please reference 80GRC021RFI0005 in any response.

Interested parties are requested to provide the following: Name and address of organization and point of contact (POC) information (name, phone, and e-mail).

d) NASA representatives may contact respondents after submittal to clarify any information submitted.

NASA will not affirmatively release any information received in response to this RFI to the public, but may use information received in developing the best approach for a contract strategy (if any), and therefore such information may be recognizable to the interested party who submitted it. Any information submitted in response to this RFI that is marked as “Confidential Commercial or Financial Information” will be considered as voluntarily submitted in accordance with the Freedom of Information Act.

In accordance with FAR 15.201(e), responses to this notice are not offers and cannot be accepted by NASA to form a binding contract. NASA is under no obligation to issue a solicitation or to award any contract on the basis of this RFI.

NASA will not pay for any information solicited under this RFI. No solicitation exists; therefore, do not request a copy of a solicitation. If a solicitation is released it will be synopsized on SAM.gov. It is the interested party’s responsibility to monitor this website for the release of any subsequent solicitation or synopsis.

[End of RFI]