Reference no: EM132668432
Project in Advanced Thermal and Fluid Engineering
Propeller analysis of a drone using Blade Element Method
1. About the project
The Blade Element Method (BEM), also called Blade Element Theory (BET) is introduced in this project for analysing the thrust, torque and power of propellers. In this project, BEM will be used to conduct aerodynamic analysis of a drone. Only vertical motion of the drone is considered. An Excel spreadsheet is provided in this project for calculations (you can find its user manual in the spreadsheet). Section 2 is the assignment. Section 3 is the instruction of the definitions and BEM formulae. Appendix A presents the detailed explanation of BEM theory, and Appendix B presents a MATLAB code based on the flow chart in Section 2.
2. Assignment
Students need to write a report to complete all the assigned questions in this section. In each question, you need to clearly explain (using not only formulae but also words) how the calculation are performed and clearly present the procedure. You will lose marks if you only give answers.
The drone has four identical propellers and each propeller has 2 blades. In this project, we only discuss the vertical motion of the drone. The geometric and operation parameters listed in Table 1 are related to student ID. Using wrong data because of using wrong student ID will cause a zero mark of the report.
The drone is moving up with a constant velocity U. In the following questions, please using the above listed parameters if they are not given or asked.
List of questions:
(1) You need to answer all the questions in this part. You need to clearly explain the procedure you have followed to complete this work, and discuss how the velocity affects the performance of the drone.
a. What is the maximum weight the drone can lift (the thrust at zero velocity)?
b. The thrust and torque will become negative if the U is sufficiently large. Find out at what velocity U the thrust and torque change from positive to negative (i.e. the thrust is zero). A numerical method for finding out U where thrust is zero is given in Appendix C.
c. Use a well-designed diagrams to show the variations of the thrust, torque and required motor power with the velocity U. An example is to use thrust-versus-U curve for thrust.
(2) If the total mass of the drone is (50+5k) kg (k is the last digit of your student ID) and the drone is accelerating vertically from a static state (using a very small value of U=0.0001 m/s), what would be the acceleration of the drone and its direction? Using graph to show how the acceleration is related to the vertical velocity (for example acceleration vs velocity diagram). Present the procedure (steps) for the calculation.
(3) If the total mass of the drone is (50+5k) kg (k is the last digit of your student ID), find out what is the minimum rotational speed and motor power required to lift the drone up at a velocity of U=1 m/s (See appendix D). You need to clearly explain how you find out the answer. Power is the product of the torque and angular speed.
(4) The four propellers are replaced by one single propeller with a propeller disk area the same as the sum of the original four propeller disk areas. The disk area of a propeller is πD2/4. The total mass of the drone is the same as the mass of question (3), find out what is the minimum rotational speed and motor power required to lift the drone up at a velocity of U=1 m/s. Compare the motor power with the motor power calculated in question (3). You need to clearly explain how you find out the answer and show the procedure/steps. (25% marks)
Question 6 and 7 are optional (no extra or bonus marks for completing optional task). You do not need to include them in the report. These two questions are for those students who are interested in some more investigation.
(5) Develop a MATLAB code based on the flow chart in Section 3 for calculating thrust and torque of a propeller. This optional task give you a chance to practice applying MATLAB in propeller aerodynamic design.
(6) The BEM method is an empirical method that involve assumptions and simplifications. What are its assumptions and simplifications that could cause errors? You need to find out answer of this question in literature, not in this document.