Microturbine III Senior Design 05002
Micro Turbine III
Senior Design Project 05002
Preliminary Design Report
Design Team:
Lincoln Cummings
Joseph Calkins
Mark Fazzio
Allison Studley
Executive Summary:
This report discusses in detail the work done by the Micro Turbine III design team throughout the design process thus far. The objective of the design project is to scale down the size of the system for implementation onto a Micro Air Vehicle (MAV).The parameters are that the micro turbine generator is to produce 5 watts of continuous power, have a system weight under 45 grams, and sized to fit within a MAV.The goals, procedures, analysis and other aspects of the design process are discussed throughout this technical paper. Much of the research and development of a feasible Micro Turbine design has been previously completed by the 04013 senior design team from last year. A Miniature Turbine is a feasible replacement for the current battery power on the RIT -MAV. Although last year’s design proved to provide enough power for all of the electronics on the MAV, the overall design was much too large to be implemented into the MAV airframe. By creating a Micro Turbine system which has advantages over the current battery power supply such as higher power to weight density, and decreased costs, the capabilities of the MAV can substantially increase.
In order to provide as many possible improvements upon the previous design, new concepts were brainstormed, developed, and investigated further. Comparisons between the previous research and these concepts were made in several dimensions. Aspects such as weight, size, cost, availability, and ease of production were used to compare the different concepts and determine their feasibility. As a result of these comparisons, it was determined that the previous turbine design was most feasible due to time constraints, limited man power and a fixed budget. Other aspects of the design such as the fuel canisters, housing, fuel supply system, and also use of exhaust gases for reducing the drag on the plane were either newly designed or modified from last year’s design.
The design of the Micro Turbine III was done through the use of the Engineering Design Process which consists of twelve different facets. Only six of the facets were used in the development of the preliminary design and are discussed throughout this document. Each of these facets is contained in its own chapter, which discusses the facet in detail.
Through the use of the Engineering Design Process, a new Micro Turbine design was developed that allows the system to be implemented into the MAV airframe. By using aspects of the previous designs along with some newly developed concepts, the system was not only made more compact, but may also possibly decrease the drag on the MAV. These designs and concepts must now be validated through the development of prototype systems which can be tested and analytically compared to the theory.
Table of Contents
Executive Summary:
1.0 Recognize and Quantify the Needs
1.1 Mission Statement
1.2 Project Description
1.3 Scope Limitations
1.4 Stakeholders
1.5 Key Business Goals
1.6 Top Level Critical Financial Parameters
1.7 Financial Analysis
1.8 Preliminary Market
1.9 Secondary Market
1.10 Order Qualifiers
1.11 Order Winners
1.12 Innovation Opportunities
1.13 Background Research
1.14 Formal Statement of Work
1.15 Organizational Chart
2.0 Concept Development
2.1 Subgroups
2.1.1 Housing Team
2.1.2 Turbine Team
2.1.3 Fuel System Team
2.2 Housing Concepts
2.2.1 Bearings
2.3 Turbine Concepts
2.4 Fuel System Concepts
2.4.1 Fuel
2.4.2 Tubing & Connectors
2.4.3 Flow Regulation
2.5 Generator
3.0 Feasibility
3.1 Turbine Feasibility
3.2 Housing Feasibility
3.3 Bearing Feasibility
3.4 Fuel System Feasibility
3.4.1 Fuel Feasibility
3.4.2 Tubing Feasibility
3.4.3 Flow Regulation Feasibility
4.0 Objectives and Specifications
4.1 Objectives
4.2 Performance Specifications
4.3 Design Practices
4.4 Safety Issues
5.0 Design Analysis & Synthesis
5.1 Turbine Analysis & Synthesis
5.2 Housing Analysis & Synthesis
5.2.1 Housing FEA Analysis
5.2.2 Shaft Selection & Analysis
5.2.3 Bearing Selection
5.2.4 Coupling Selection
5.3 Fuel System Selection & Analysis
5.3.1 Fuel Selection
5.3.2 Tubing & Connectors Selection
5.3.3 Flow Regulation
5.3.4 Fuel System Analysis
6.0 Future Plans
6.1 Test Setup
6.2 Schedule
6.3 Budget
7.0 Conclusion4
A.Appendix A – Turbine Performance Graphs
B.Appendix B – Turbine Performance Data
C.Appendix C – Mass Flow Calculation D. Appendix D – Finite Element Analysis On Housing / Cap
D.Appendix D – Finite Element Analysis On Housing / Cap
E.Appendix E – Turbine Performance Data
Figures, Tables, and Equations
Page / Title13 / Fig 1-1: Capstone Micro Turbine
14 / Fig 1-2: MIT's Micro Turbine & Test Stand
17 / Fig 1-3: Organizational Chart
19 / Fig 2-1: Housing Concept
20 / Fig 2-2: 3-D Pelton Wheel Turbine
33 / Fig 5-1: Blade
33 / Fig 5-2: Turbine Design
35 / Fig 5-3: Cap FEA
36 / Fig 5-4: Housing FEA
42 / Fig 6-1: Schedule
43 / Fig 6-2: Budget
25 / Table 3-1: Housing Feasibility
26 / Table 3-2: Bearing Feasibility
33 / Eqn 5-1: Blade Calculation
34 / Eqn 5-2: Torque
34 / Eqn 5-3: Efficiency
40 / Eqn 5-4: Density
40 / Eqn 5-5: Velocity
40 / Eqn 5-6: Mass Flow
1.0 Recognize and Quantify the Needs
1.1Mission Statement
The purpose of the 05002 Senior Design team is to design and build a working prototype of a micro-turbine generator that can be integrated into a MAV airframe and power the vehicles electrical accessories. The micro-turbine design is to be a continuation and improvement upon the previous design team’s project through the use of much of the previous research and design along with new research and design to create a baseline for integration into the MAV airframe.
1.2 Project Description
The current RIT MAV vehicle’s motor and electronics are powered by a heavy and expensive Lithium Ion battery. Although these batteries supply the proper electrical capabilities, it has been proven through previous research and senior design teams that a more lightweight and compact power supply is feasible. The scope of the current project is to improve upon the previous year’s designs and to implement the design into the MAV airframe, which has not been done by previous teams.
As a result of last year’s senior design team, there is an existing Pelton wheel turbine design which can be used in this years design. Other turbine designs, as well as other Pelton wheel designs will be investigated and their feasibility will be determined compared to the current design. Last year’s design produced the necessary power requirements, however was much too large to be implemented into the MAV airframe.
This year’s team will research different turbine designs, propellants, and other components and evaluate their feasibility and advantages/disadvantages over the current design. One of the major goals is to make a smaller housing which will be able to fit into the MAV airframe as well as be lightweight, robust, and fulfill the required power and flight requirements. The MAV requires a minimum of 5 watts of power for use by the onboard electronics. In order to achieve these power requirements, the turbine must rotate at high speeds, which last year’s team determined to be around 100,000 rpm. While designing the new system, the overall weight goal of 45 grams must be considered.
1.3 Scope Limitations
Through previous senior design research, it has been determined that a minimum of 5 watts of power is needed in the flight of the RIT MAV. This requirement sets a limitation on the micro turbine to produce a minimum of 5 watts of power for sustainable flight. As mentioned previously, the weight of the system is also an issue to improve upon the current battery power. A goal of an overall weight including propellant tanks is a reasonable 45 grams.
Many of the limitations to research and design parameters are due to the limited amount of time as well as a project budget of $1000 - $1500. The budget is to be supplied by the Kate Gleason College of Engineering.
1.4 Stakeholders
The primary stakeholders in this design project are the members of the design team. In addition to these persons is the faculty of RIT’s Mechanical Engineering Department. Dr. Jeff Kozak, the teams advisor and contact, is the dominate member of the faculty who will benefit from this year’s project in advancing the design onto future microturbine design teams along with MAV teams.
Secondary stakeholders include the outside venders sought for the manufacture of intricate parts. Also on this list are faculty and staff of other RIT departments including the Microelectronics Department and those in the Brinkman Laboratory. Stakeholders extend onto member of other current and future MAV design teams at RIT and other schools involved in microturbine research.
1.5 Key Business Goals
A successful project will be defined by the evidence of a working micro turbine prototype producing five watts of power, weighing less than 45 grams, and sized to be implemented onto a MAV. If the design team is capable of completing the task, then much will have been accomplished. Not only will the core objective of the project be achieved, the students on the team will have also gained a valuable experience in working with a multidisciplinary team. The results of this project will serve as a stepping stone for further development in this field. Success of this project will bring future research a step closer to replacing the power source on MAVs, which is the ultimate goal.
1.6 Top Level Critical Financial Parameters
Almost all of the budget will be used for purchasing of raw materials or sub-assemblies. The goal is to have the micro-turbine design be within a reasonable amount of a battery powered system. The prototype will use nitrogen gas in large canisters, the goal for future micro-turbine teams is to shrink the weight and size of the nitrogen canisters and piercing components so that they can be incorporated onto an MAV airframe.
1.7 Financial Analysis
The project has a tentative budget of $1000 from the Mechanical Engineering department at RIT. This will be used to fund purchases of all the components listed in the Bill of Materials (see appendix XXX). The major components that will be ordered are the following:
- Housing material
- Fuel canisters
- Puncture system for the fuel canisters
- Turbine
- Internal components: shaft, bearings, couplings
- Machining costs: housing
1.8 Preliminary Market
The project team two years ago conducted a proof of concept project, while last year’s team designed a functioning prototype. That project initiated a host of long-term research projects. Therefore, the work being done is still set in the research realm while concern for actual implementation onto an MAV is under heavy scrutiny. The primary customer for this year’s project remains academia. Eventually these efforts and research will develop into a feasible energy source that the RIT MAV team can utilize for efficient flight.
1.9 Secondary Market
Through added time and research, this design could be developed into a reliable source of lightweight energy production. There are numerous applications for such products. The Department of Defense (DoD) and the Forest Service are currently interested in utilizing MAVs for their particular needs. The DoD is interested in using MAVs in military conflicts for ground personnel to utilize as scouts or forward observers. The Forest Service would like MAVs to fly into and around forest fires and monitor their status to help better direct fire fighting efforts. However, the product is not limited to MAVs. This lightweight energy production is open to a host of other applications. Micro robots that could be made lighter and smaller using micro turbines are a good example of this. The micro turbine is open to numerous applications in the future.
1.10 Order Qualifiers
The purpose of this research design is to improve upon the technology that has already been produced at RIT. Therefore, the senior design team must produce a prototype micro turbine/generator system that is sized to be more suitable for MAV application than last year’s design in addition to including the fuel system into the design. To be more useful, the power produced shall be reduced from 18 W to 5 W. This is the power required by a MAV flight production. The weight must also be held to less than 45 grams. This will make the product more feasible for MAV application.
1.11 Order Winners
If time and money permit the team will work to complete the following goals:
- Implement the fuel system into the design.
- Optimize turbine efficiency.
- Maintain the ease of assembly and disassembly of the turbine/generator system.
- Improve bearing setup and design.
- Improve the housing design to better fit an MAV.
- Be safe to users and environment.
- Validate data using Computational Fluid Dynamics modeling.
- Design and test all components for form and function.
1.12 Innovation Opportunities
In this day and age, persons in all industries are looking to maximize efficiency while minimizing the materials required. Microturbines strive to achieve the same goal in providing an alternate power source. Since everything is on the micro scale, the complete package will be light in weight and compact in sized. Research in these turbines will aid any electrical required applications limited by space and weight.
1.13 Background Research
The term micro turbine has become undefined as its definition changes from field to field. It can be used to describe a stand-alone unit producing hundreds of kilowatts in industry to a Micro Electrical Mechanical System (MEMS) producing milliwatts of power in academic institutions. A wide range of applications in industry see the potential for micro turbine generators for electricity. The primary use for micro turbines is in the growing Unmanned Aerial Vehicle (UAV) and model airplane markets. Institutions throughout the country are currently designing micro turbines on the micrometer scale.
The high efficiency of micro turbines has led industry to scale down power producing turbines from thousands of megawatts to tens of kilowatts. Capstone Turbine Corporation remains the world leader in the micro turbine market since introducing their products in 1998. These highly efficient turbines are used for everything from hybrid electric vehicles (HEVs) to providing power to hotels and office buildings. By utilizing a wide variety of fuels, these generators are able to be used in remote locations.
In the commercial market, micro turbines are generally aircraft turbines scaled down to be sized appropriately. These turbines produce just a few pounds of thrust sufficient for UAVs, Missiles, and remote controlled aircraft. The continuous growth in the autonomous missile and UAV markets is being pushed by the military. NASA and the defense department hold numerous contracts for research and production of micro turbines. Unfortunately, these micro turbines are too large for MAV applications.
Research is being conducted at universities throughout the nation and around the world. This research is on the scale in which RIT has been performing its work on the topic. A number of institutions are furthering research in the realm of power production on the milliwatt scale to a few watts. MIT is the currently leader in this field. Other work is being done at Stanford and SimonFraserUniversity. The work being done at each of these institutions is of a different nature.
MIT is leading the micro turbine research market due to their heavy funding provided by the Defense Advanced Research Projects (DARPA) along with other defense agencies. Due to this fact, much of their work remains unpublished while it is in the development stages. Figure 1-3 represents the radial flow reactive compressor, combustor and turbine system being developed by MIT. The greatest difficulty with this design is in the bearings, which are unable to withstand the high rotations per minute. The goal of this project is to produce approximately ten to twenty watts of power based on liquid hydrogen fuel. Alternative fuels such as hydrocarbons could produce up to a hundred watts of power.
Stanford and SimonFraserUniversity are focusing their work on new manufacturing techniques to be used to produce highly specialized turbines. Stanford is developing a Mold Shape Deposition Manufacturing (Mold SDM) process to produce complex silicon nitride parts. While they have not testing a compressor and turbine system, compressed gas testing has proven the turbine to be successful up to 456,000 rpm. Figure 1-4 shows an example of some of the Stanford’s designs. SimonFraserUniversity is using a design already tested in nuclear magnetic resonance (NMR) spectroscopy of solid samples. Using this technology, impulse radial inflow turbines were produced in sizes ranging from 10-2.2 millimeters in diameter. Samples of these spun by compressed nitrogen have shown to function up to 1,000,000 rpm.
The research and development at RIT began just three years ago with a proof of concept senior design project. During this project, headed by Dan Holt, a dentist drill was used to spin a generator. Holt continued the project on with his master’s thesis, in which he expanded into the realm of using a compressed gas to drive a turbine which in turn spins the generator. Last year’s design team continued the efforts of Holt by designing and producing a functioning micro turbine generator. This design was a great achievement for RIT in developing a usable design for Micro Air Vehicle (MAV) applications. However, the prototype from last year remained too large and heavy for use on a MAV. In addition, the fuel system was not included in the design. The current project described within this report aims to reduce the size and weight of the system, as well as implementing the fuel storage and delivery system into the overall design.