Determining Optimum Placement of Plasma Actuators in Commercial Airplanes - Prof. Daniel R | Study Guides, Projects, Research Mechanical Engineering

Submitted on October 22, 2008.

Senior Design I Dr. Kirk

Questions & Comments on Midterm Presentation

PIFAS TEAM

1) What methods will u use to determine placement of actuators? Can different

aircraft be affected with more benefit results than other ones? How will you

choose an A/C to “optimize”?

PIFAS plans to conduct a series of experiments to determine optimum placement of

actuators (This is the main goal of the project). While the benefits of this system may

affect aircrafts in different ways, the design project has been tailored to investigate its

relevance for commercial airplane (See Reynolds matching in “Spec’s” slide for a

cruising Boeing 747) Relevant A/C signal frequency, amplitude, etc. will be

determine from experimental data to minimize power required by the system.

2) Doesn’t insulation the ends of the actuator simply create “new ends” from which

u get the edge effects?

Every plasma actuator is composed of two copper wires separated by a layer of a

dielectric material such as Kapton tape. The dielectric material prevents ionized

particles to actually reach the copper wires. On the original set up, however, once the

copper wires protruded at the edge of the plate with no type of insulating material, the

high voltage difference between the two wires caused a plasma arc which directly

contacted the wires and the fiberglass siding, causing burning and charring of

materials. By insulating the protruding wires (polyethylene, vinyl, etc.) at the free

edges until well within (approximately 0.5”) inside the Kapton tape, the team can

avoid the charring problem. No “new ends” will be created since the dielectrics will

overlap at one edge while the wires will be significantly apart at the other extremities

which will prevent any undesirable plasma arc creation outside of the plate’s surface.

3) What exactly are you doing that hasn’t been done before? Good thought process

behind “system efficiency slide”. What part of navier stokes- seemed to have no

bearing on calculations. I don’t catch why CTE exp. was performed for this

design proj. Feels like presentation has too much “in house” terminology. Slow

down for those of us trying to understand your project.

The specific placement of plasma actuator in regards to location along the chord line,

numbers of actuators required, voltage and frequency, and minimum power required

have yet to be calculated for a plasma actuator system. It is PIFAS goal to obtain

these optimum conditions through experimental data and hopefully corroborate the

results as a cost effective system for improvement of airplane performance. At the

preliminary stages of the project, PIFAS believed that the exposed wire and top

surface of the dielectric would experience very high temperatures due to the close

proximity to the generated plasma. This overheating of the dielectric material, which

was initially bonded to the lower fiberglass surface through an epoxy- resin, could

introduce a series of structural problems such as delamination, copper wire

misalignment, among others. In addition, at the preliminary stages of the project,

PIFAS had access to a variety of polymers suitable to act as dielectric materials, yet

had no information on the material’s specific identification and a literature search

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Submitted on October 22, 2008. Senior Design I Dr. Kirk

Questions & Comments on Midterm Presentation

PIFAS TEAM

What methods will u use to determine placement of actuators? Can different aircraft be affected with more benefit results than other ones? How will you choose an A/C to “optimize”? PIFAS plans to conduct a series of experiments to determine optimum placement of actuators (This is the main goal of the project). While the benefits of this system may affect aircrafts in different ways, the design project has been tailored to investigate its relevance for commercial airplane (See Reynolds matching in “Spec’s” slide for a cruising Boeing 747) Relevant A/C signal frequency, amplitude, etc. will be determine from experimental data to minimize power required by the system.
Doesn’t insulation the ends of the actuator simply create “new ends” from which u get the edge effects? Every plasma actuator is composed of two copper wires separated by a layer of a dielectric material such as Kapton tape. The dielectric material prevents ionized particles to actually reach the copper wires. On the original set up, however, once the copper wires protruded at the edge of the plate with no type of insulating material, the high voltage difference between the two wires caused a plasma arc which directly contacted the wires and the fiberglass siding, causing burning and charring of materials. By insulating the protruding wires (polyethylene, vinyl, etc.) at the free edges until well within (approximately 0.5”) inside the Kapton tape, the team can avoid the charring problem. No “new ends” will be created since the dielectrics will overlap at one edge while the wires will be significantly apart at the other extremities which will prevent any undesirable plasma arc creation outside of the plate’s surface.
What exactly are you doing that hasn’t been done before? Good thought process behind “system efficiency slide”. What part of navier stokes- seemed to have no bearing on calculations. I don’t catch why CTE exp. was performed for this design proj. Feels like presentation has too much “in house” terminology. Slow down for those of us trying to understand your project. The specific placement of plasma actuator in regards to location along the chord line, numbers of actuators required, voltage and frequency, and minimum power required have yet to be calculated for a plasma actuator system. It is PIFAS goal to obtain these optimum conditions through experimental data and hopefully corroborate the results as a cost effective system for improvement of airplane performance. At the preliminary stages of the project, PIFAS believed that the exposed wire and top surface of the dielectric would experience very high temperatures due to the close proximity to the generated plasma. This overheating of the dielectric material, which was initially bonded to the lower fiberglass surface through an epoxy- resin, could introduce a series of structural problems such as delamination, copper wire misalignment, among others. In addition, at the preliminary stages of the project, PIFAS had access to a variety of polymers suitable to act as dielectric materials, yet had no information on the material’s specific identification and a literature search

could not be performed to obtain the required values. For this reason, PIFAS performed their own CTE experiment to ensure materials’ CTE would match within reasonable tolerances.

How do you quantify maintenance cost of the actuators? What makes the project different from some of the Lit. Review papers? The method for quantifying the maintenance cost of the actuators has yet to be determined, but a preliminary scheme where actuators are on for a period of time at high power and/or cycled through on-off states for a maximum number of cycles to test the component’s life span has been considered. See Answer 3 regarding PIFAS project goal. Overall, the idea is to weigh the costs of replacing, maintaining or upgrading an aircraft with the actuator system vs one without it. If fuel consumption is reduced covering or exceeding the costs of the mentioned system then it would present a major profit for all future airlines.
Roughly what do you think the weight of the system would be, saying how much more weight your adding because 0.5% will be burned pretty easily? Systems total weight requires an examination of component quality and cost since it is while most transformers are fairly heavy, it is possible to obtain lightweight pieces for a higher cost. In the end, the total weight will depend on the experimental results (i.e. will 20 actuators be required along the chord line of the airfoil or will 3 suffice to obtain an approximate aerodynamic performance, significantly reducing power requirements…) Therefore, this is a specification which PIFAS would like to clearly calculate and show in the future. Initial estimates indicate that the equipment would weigh around 40 – 50 Kg based on similar existing systems. This however is very little compared to a 1% reduction in drag which would results in around 10% increase of the airplanes maximum weight capacity.
Extreme detail about technicalities and calculations really necessary? While it is our effort to explain calculations and their relevance to the project in a clear manner and as concise as possible, PIFAS team believes the former takes precedence over the latter. It is not the calculations but the process of thought which PIFAS believes needs to be depicted in a comprehensible manner, and we will continue to thoroughly explain the calculations if pertaining to the project’s progress. Of course, in order to minimize time, previously well defined methodology and/or thoroughly explained calculations may not be repeated to the same level of detail and assumed understood for future presentations. PIFAS team would rather err on the side of presenting too much detail than assuming the audience’s understanding of the subject matter.
Will you attempt to solve the electric field BVP, instead of the simplification? What about an endurance comparison, TSFC, etc? PIFAS will focus their efforts to optimize the prescribed objective set forth in the presentation. These quantities by themselves are known in general to affect airplane performance and can singularly express the effectiveness of the plasma actuator system. However, once these are obtained, calculations of endurance, Isp, TSFC, and

varied simultaneously in ways not described in past papers (varying frequency, angle of attack, actuator on-off combination). As mentioned in the question, PIFAS does suspect that there exist optimum locations for actuators to meet desired objectives with minimum power consumption. (It is the driving premise of this senior design project). Another point to keep in mind is that the first experiment presented was intentionally tailored to the same specifics as the literature ones. By doing this we can establish the validity or our results and therefore continue with our own research with confidence.

Why didn’t you factor in initial cost? This seems important to cost analysis. PIFAS understands this question may refer to initial monetary costs of implementing plasma actuators for either the purposes of this project or future commercial usage. In the case of the former, PIFAS has been committed from the beginning to either obtaining the necessary funding through sponsorships or internally financing the project. In regards to factoring the initial cost for companies planning to implement the usage of plasma actuators, this is part of the total cost analysis. The slide 28, which included two bullets detailing the effort to account for serviceability and maintenance cost of plasma actuators and not JUST initial cost, failed to include this detail, providing a very different meaning to the information with the absence of the word “just”. PIFAS would categorize this error as a grammatical mistake and considers the initial cost of components and power supply an instrumental piece in cost analysis.
Lorentz forces? The magnitude of the magnetic field and its effects on the overall aerodynamics of the flow seem to be negligible for low speed flows (M < 1) and the influence of the electric field dominates over the ionized particles’ behavior. In many cases on published research, the effects of the magnetic field and consequent Lorentz forces has been neglected while still maintaining accuracy between simulation and experimental data. PIFAS would note that the effects of the electric field diminishes while the magnetic field effects become more significant as the flow reaches high supersonic and enters hypersonic flow regimes (M > 5). In this case, the flow dynamics may then need to be expressed, sometimes solely by, the Lorentz forces and include the effects of the magnetic field. One of the main factors that makes the Lorentz factor negligible in our experiment is that the magnetic field created in our setup is too low to have any effect.
Spare us the physics lessons. Too many questions! Did u run your numbers through FEA, Matlab, ANSYS? PIFAS has yet to construct a fluid model of the plasma interaction with the free stream flow and therefore, no usage of FEA or ANSYS has been required. Most calculations have been performed on EXCEL due to its simple interface and accessibility by all team members at any given time. In regards to the physics lesson, please refer to Answer 6. Also, please note that performing many of these calculations in software like fluent and other is currently being done by organizations

such as NASA with varying results. At the suggestion of our faculty advisors and other professionals in the area, we will not attempt to solve our problems using such complicated models that go even beyond graduate level until we have a better understanding of the system itself.

Move specs slide towards front of slide show. What are dielectrics? Too much text on some slides. Will there be an option to put these actuators on a real plane to test the energy comparison? Talk louder if possible (most people knew their slides). @#*(#@((# flat plate with given wind tunnel apparatus. The dielectric material was very thoroughly explained (to the dismay of many) during the presentation, from its function to important properties to material selection to dimensioning. In short, dielectrics are non-conducting materials that insulate against electric, magnetic, and electromagnetic fields. PIFAS refers the reader to the presentation slides for further review. The location of the “Spec’s” slide was chosen so as to follow logically from the project’s thought process. It was inserted immediately after the explanation of the dielectric material and its function since a number of the specifications entailed properties of the dielectric material (dielectric constant, dielectric strength, dielectric material’s resistivity, etc.). It was determined that a justification for the chosen values would be lacking if not properly explained in preceding sections. Depending on the response and support from contacted companies for sponsorship, PIFAS will investigate the feasibility to perform testing during actual flight.
Does an existing aircraft produce enough excess usable power to power this system? What is the deliverable? PIFAS has yet to investigate whether the plasma actuator system may be powered from excess power produced by current aircraft engines. Currently, the total system is being considered as stand alone with its own power source (Power supply, transformer, etc) If time permits, this will be an area of great interest in order to decrease overall system weight and consequent cost.
How do your electric equations relate to N-S equations? How can you be sure you are only ionizing N2? Can you refine your E equations? While the ionization of Nitrogen or Oxygen may be determined in a variety of ways, PIFAS has elected to go for a low cost, qualitative way to ensure N 2 ionization without undesirable Oxygen ionization. This can readily be determined by the color of the plasma arc, which would maintain a purple color during Nitrogen only ionization, but would change to a bright white color when Oxygen begins to ionize. In this way, PIFAS may record threshold frequencies for desirable operating range and hopefully determine a trend for the threshold frequency variation with free stream velocity.
Did you reference yourself? Why did you perform CTE experiment? How? How do you ionize the air? Please see Answer 3 in regards to CTE experiment. The experiment was not described in detail since the results were not very accurate and did not impact

Determining Optimum Placement of Plasma Actuators in Commercial Airplanes - Prof. Daniel R, Study Guides, Projects, Research of Mechanical Engineering

Partial preview of the text

Download Determining Optimum Placement of Plasma Actuators in Commercial Airplanes - Prof. Daniel R and more Study Guides, Projects, Research Mechanical Engineering in PDF only on Docsity!

Questions & Comments on Midterm Presentation

PIFAS TEAM