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Proceedings of the Multi-Disciplinary Senior Design Conference

ADVANCED ATOMIZATION TECHNOLOGIES TEST CHAMBER CALIBRATION FLUID EXHAUST SYSTEM

Hayden CummingsMechanical Engineering

Adam FarnungMechanical Engineering

Andrew HeuserMechanical Engineering and Civil Engineering

Technology

Zach HustonIndustrial and Systems Engineering

Robert MoshierMechanical Engineering

Timothy NicholsMechanical Engineering

Faculty Advisor

Gary WerthRochester Institute of Technology

Abstract:

The fuel injection nozzle testing chamber is used to calibrate the spray angles and flow rates of fuel injection nozzles used in aircraft. The chamber provides an air-tight, safe environment to perform the testing. This system incorporates the nozzle-block off for flow testing with the measurement system for angle testing into one location. This consolidation of processes reduces the cycle time of the test and reduces the time and number of occurrences of the calibration fluid being exposed to the air.

Introduction:Advanced Atomization Technologies is a joint venture between General Electric Aviation and

Parker Aerospace. AAT specializes in the manufacturing and testing of fuel injection nozzles for gas turbine engines. The fuel injection nozzle testing chamber is a system used to test the flow of calibration fluid through the nozzle and measure the spray angle of the fluid through the nozzle. The system being used, which prompted the redesign, caused safety issues to the operators and discomfort to all employees within the building. The calibration fluid used for testing has an offensive smell that is poorly contained within the current chamber. Due to this poor containment the odor permeates the entire building causing general discomfort and migraines. The focus of this project was to redesign and prototype a chamber that more effectively contained the calibration fluid.

The design of the chamber was chosen for multiple reasons, the containment of the calibration fluid during loading, reduced cycle time and operator handling, and a more effective method of performing relevant tests.

Copyright © 2008 Rochester Institute of Technology

Proceedings of the Multidisciplinary Senior Design Conference

Process:In Multidisciplinary Senior Design 1 (MSD 1), the project was introduced and defined through

the Project Readiness Package. This document both introduced the problem that needed to be solved as well as parameter guidelines and design constraints. From these details, along with customer input from AAT, a set of customer requirements were developed which allowed for organization and prioritization of key features of the solution. Through the first phase of MSD 1, these requirements were reviewed and refined until there was unanimous agreement between the engineering team and the customer that the list was both accurate and complete. Figure 1 shows the completed customer requirements table.

Figure 1: Customer Requirements

The next step was to distill and parameterize this list of customer requirements in order to create a table of engineering requirements. This table needed to map to all of the original customer requirements while describing them fully by function, metric, unit of measure, and marginal and target values. Engineering requirements are necessary because, while the customer requirements describe what the system needs to achieve, engineering requirements give something to design to. Again, this was an iterative phase and utilized correspondence with the customer in order to achieve accurate descriptions and parameter values. Please see Figure 2 for a complete list of engineering requirements.

Figure 2: Engineering Requirements

In addition to giving design points for specific parts of the solution, engineering requirements allow for isolated testing once a prototype solution is built. As an example, the first engineering requirement, S1, for air quality can be directly tested and measured in PPM (parts of contaminant per million parts of air) once the prototype system had been built.

Using both the customer requirements table and the engineering requirements table, a risk analysis was performed in order to predict issues that might arise during the project or with the prototype solution upon completion. This process was multifaceted; first, it was a crucial step in determining what tests would need to be performed using the prototype in order to assure that the system worked properly and achieved the design goals. Secondly, the risk analysis showed what major risks may occur based on likelihood and severity which allowed for risk abatement and mitigation.

Project P15681


Using both the customer requirements table and the engineering requirements table shown, a house of quality was built. The purpose of this third table is to determine relative importance of each requirement by creating a matrix of the two sets of parameters. Using this information, it could be determined which requirements should receive the more prioritized attention based on compounding importance by use of a house of quality.

Design:After going through the process of concept selection in MSD 1, a final design was chosen based

upon various Pugh charts and other concept generation processes. In the design that was ultimately chosen, many different sub-systems had to come together and work in unison to achieve the desired goal set by AAT. The main sub-systems are as follows; Nozzle Mounting, Glove Integration, Probe Measurement system, Vacuum System, Drainage, and the Seals.

Nozzle Mounting:

Figure 3: Nozzle Mounting

Mounting the GE90 nozzle correctly was crucial to the design of the chamber and particularly to the measurement system. The current setup at AAT had a fixed mounting plate where the nozzle can be locked in by using a simple thumb screw clamp system. This same principle was used in the new design; however, the nozzle now mounts to a separate fixture that can be loaded and unloaded outside the chamber. Once the nozzle is loaded into the cradle, it is placed in the testing chamber and locked down (See Figure 3). Movement of the cradle once inside the chamber needed to be minimized to ensure the nozzle does not shift position during testing.

Glove Integration:



Figure 4: Glove Integration Model

Figure 5: Glove Integration

Flow rate testing is done by blocking off the outer primary and secondary tips. Blocking off of the tip needed to be quick and easy and in order to minimize testing time, the operators need to be able to reach inside the chamber to change the tip block off locations. In order to achieve this, ports to the side of the chamber were added (See Figures 4 and 5). These ports allow the gloves to be slipped over an outside retaining ring and then clamped in place. One of the main challenges with this solution was glove selection. The gloves need to be able to withstand the calibration fluid itself as well as the depressurization of the chamber during the pump out cycles. Due to the pressure difference inside and outside the chamber, the gloves tend to want to expand like a balloon inside the chamber. Testing was done and the gloves chosen were a fabric lined PVC coated glove.

Probe System:

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Figure 6: Probe System

The probe system is being used for the measurement of the spray angles of the nozzle itself. These probes are mechanically driven using a motor and gearing system. The probes themselves are threaded which allows them to drive in and out of a fixed plate when the motor is run in either forward or reverse. One of the requirements by AAT was that the same level of accuracy in the probe system needed to be kept in order to meet the standards set by GE. The threading on the probe combined with the gear ratios and the control of the motors allow for an accuracy of measurement of 0.0002 in, which is more accurate than AAT’s current method. Figure 6 shows a full model of the probe system in relation to the nozzle and cradle above it.

Vacuum System:

Figure 7: Vacuum System

One of the main customer and engineering requirements was improving air quality. The new chamber needed to better contain the fluid and the odor than the old chamber did. The vacuum system developed allows for constant negative pressure on the chamber during testing as well as a full purge cycle after testing. The pump chosen is an AER model CM300 (Seen to the left in Figure 7). With the aid of an automated butterfly valve, the pump can draw out air from the chamber at ~100 CFM or 300 CFM. During testing the chamber is sealed and the pump provides a constant suction of ~100 CFM. This is done to increase visibility in the chamber during testing. When testing is complete, the valves close and



the pump runs at 300 CFM for roughly 3 seconds. Once complete, the valves again open allowing the nozzle to be removed.

Custom modifications were made to the pump. An aluminum impeller is used to ensure operating temperatures will not exceed the flash point of the calibration fluid, 104 oF. In addition, a charcoal filter was added to the exhaust side of the pump to reduce any odor that is evacuated from the chamber.

Seals:

Figure 8: Door Perimeter Seal Figure 9: Door Overlap Seal

To contain the odor, the chamber needed to be airtight. Because there were glove holes, top doors and an exhaust port, seals were created to trap odor. For the main doors on top of the chamber, an O-ring groove was cut to fully seal around the edges of the doors (See Figure 8). Where the doors meet and overlap there is an additional seal to ensure there will be no leaks (See Figure 9). Around the gloves, there are rings protruding that the gloves get wrapped around and then pipe clamped. The glove material is a PVC so when compressed by the clamp, a seal will be created.

As previously discussed, the pump runs continuously, and due to the charcoal filter, very little calibration fluid is able to make it out of the system.

Drainage:

Figure 10: Upper Chamber Drain

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Figure 11: Lower Chamber Drain

In the original design done by AAT, the drain was unable to keep up with the quantity of calibration fluid used. This resulted in pooling inside the chamber and standing calibration fluid. The engineered solution to this was to have one drainage section that has a large drain hole and a relatively small area of flat surfaces. An angled plate is used to direct all of the calibration fluid to a large drain hole. Due to the large drain hole and minimal flat space, the amount of pooling decreases. Once the fluid flows through the main drain (See Figure 10), it empties into the area that has the secondary drain which feeds back to the test stand. This secondary drain can have pooling and standing fluid. Since the main drain can completely seal off the upper chamber with an automated ball valve (See Figure 11), it has no effect on the testing or the air quality conditions.

The final prototype was delivered to AAT on April 21, 2015. Given the complexity of this project, a lot of time was needed for integration of the new test chamber with AAT’s proprietary test stand. Delivery by this date allowed ample time for integration, debugging and testing.

Results:In order to accurately assess the success of the prototype, a gauge R & R was created. This

process includes using three operators with ten fuel injection nozzles and multiple trials for each. By comparing the results of the test on the in-place system to the results from the new prototype system, we could judge the accuracy and repeatability of the new system.

The gauge R & R was centered around having a fully operating system. Due to miscommunication regarding the integration of the measurement probes to AAT’s test stand, the gauge R & R had to be modified to remove this part of the test. The gauge R & R performed was instead focused only on the flow of the fuel injection nozzles.

Due to time constraints with our customer, the flow portion had to be altered as well. In the end, 5 different nozzles were flow tested on both AAT’s current test chamber and our prototype test chamber. The results of those tests can be seen in Figure 12 below.

% Difference

Flui

d Pr

essu

re

(psi

)

BFP

F682

3

BFP

F686

4

BFP

F712

1

BFP

F623

3

BFP

F672

1



Inner Flow 25 -3% 2% -22% -2% -1%

75 -3% -3% -8% -5% 5% 135 -5% -2% -5% -6% 3% 165 3% -2% -1% -8% 1% 230 -12% -19% -25% -24% -8% 360 -31% -30% -40% -37% -28% 550 -45% -19% -50% -48% -42%Total Flow 25 4% 1% 5% 10% -3%

60 -3% 0% -5% -1% 3% 75 -2% -1% -4% -1% 2% 135 -3% 7% -5% -10% -9% 165 -1% 0% 4% -3% 0% 230 0% 0% 0% 0% 0%

Figure 12: Flow Test Results

The results of the gauge R & R were mixed. Regarding the inner nozzles, at fluid pressures up to 165psi, the nozzle flows showed strong correlation between the old and new test chambers. The same can be said at all fluid pressures regarding the total nozzle flow. At high fluid pressures when testing the inner nozzle flow however, there was a notable difference in the observed fluid flows.

The difference in fluid flows at high pressures when testing the inner nozzles was most likely due to an issue with the fluid block offs of the new system. Further testing and design revisions could alleviate this problem. Another potential fix would be to use the block off procedure that is currently used by the customer.

Conclusions and Recommendations:

While the project was an overall success, there were some issues that, if fixed, could have made us even more successful.

One of the biggest issues with our project was the scope. Our project started out simple, and quickly ballooned into an enormous task. Without doubt, we took on too much work. Instead of overhauling or modifying the current procedure and equipment, we developed an entirely new test chamber and changed the procedure for the nozzle calibration and test. Designing, building and testing a completely new system and procedure proved to be much more work than we anticipated. If we had narrowed the scope of our project to take on slightly less work, we may have been more successful overall.

Another issue was the problem at hand. Unfortunately, due to stipulations from the customer, we were forced to use some of their equipment. This equipment is located at the customer’s site which made the project difficult as we had to design with integration in mind. It also presented issues with the integration itself as we only had a few days to complete, debug, and test it.

We also quickly learned that keeping up to date on the project plan was imperative to our success. No matter how the work is laid out, unforeseen issues will always arise and throw the project plan off track. Being ahead of schedule and/or planning for these issues would greatly help us keep track all the way to the end of the project.

During the integration of the prototype, another issue was raised. The measurement system’s success was dependent on its ability to be integrated to the encoders used by AAT to actually provide the

Project P15681


metrological readout. Since this system could not be integrated, the probes could not function as designed.

Aside from these setbacks, many aspects of the project were very successful. The design of the test chamber and the changes to the test procedure greatly reduced the operator’s exposure to the calibration fluid. The system was well received by the operators at the customer’s site and, for the tests that we could run, the cycle time had dropped significantly (10% reduction) when compared to the old system.

The prototype was also very successful in being able to quickly purge all atomized fluid from the chamber quickly as well as controlling the release of any atomized fluid. This vastly reduced the amount of odor from the calibration fluid that was able to escape the system.

For future work, some changes could be made to make the system even better. The biggest return on investment would come from integrating the measurement probes properly. This would allow the system to function as designed. A better block off for the nozzle could also be designed and tested to alleviate that issue. Any aluminum parts could also be anodized to better protect them in this harsh environment.

References:

[1] Beer, Ferdinand P. Mechanics of Materials. New York: McGraw-Hill, 2011. Print.

[2] Dewey. (2007). The Learning Curve. Retrieved from http://www.psywww.com/intropsych/ch07_cognition/learning_curve.html

[3] Centers for Disease Control and Prevention (CDC). National Center for Health Statistics (NCHS). National Health and Nutrition Examination Survey Data. Hyattsville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, [2015].

[4] CAL FLUID MIL PRF 7024E TY II. N.p.: Ashland Saftey Data Sheet, 2008. Print. [5] Drake, Paul J. Dimensioning and Tolerancing Handbook. New York: McGraw Hill, 1999. Print.

[6] Vinson, Jack R. The Behavior of Thin Walled Structures: Beams, Plates, and Shells. Dordrecht, Netherlands: Kluwer Academic, 1989. Print.

[7] Shigley, Joseph E; Mischke, Charles R; Budynas, Richard G. Mechanical Engineering Design. New York: McGraw-Hill, 2010. Print.


http://www.psywww.com/intropsych/ch07_cognition/learning_curve.html

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