NUMERICAL SIMULATION AND EXPERIMENTAL INVESTIGATION OF THRUST PRODUCED BY A HOBBY–SCALE PULSEJET ENGINE

Open Access
Author:
Zhu, Mengyao
Graduate Program:
Aerospace Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
July 09, 2015
Committee Members:
  • Michael Matthew Micci, Thesis Advisor
  • Cengiz Camci, Thesis Advisor
Keywords:
  • pulsejet
  • lax-wendroff
  • numerical simulation
  • experiment
  • thrust
  • operating frequency
Abstract:
The pulsejet is a type of jet engine in which combustion occurs in pulses. It was introduced to the world in the 1860s and the most famous previous application was the “V-1 buzz bomb” during World War II. Because of its high thrust to weight ratio, low cost and simple design, the pulsejet has recently received more research interest, like micro-scale propulsion devices for UAVs, or even large-scale propulsion devices for single stage to orbit Launchers. The objectives of this research include investigating the thrust a hobby scale pulsejet can deliver and its operating frequency, and develop a numerical simulation model for future study. This project investigated pulsejet operation in a combined numerical and experimental approach. The working mechanism of pulsejet engine was studied and a numerical simulation code based on a shock tube model with a quasi-one-dimensional assumption was built using second-order accurate Lax–Wendroff scheme. The code was capable of predicting flow parameters at various locations of the pulsejet engine with different lengths and diameters. A test bed with mounting clamps was manufactured; 10 tests were run on gaseous propane with assistance from an air compressor. The simulation model estimated the 40 cm pulsejet can deliver an average 4.18 N thrust with a 232 Hz operating frequency and the maximum instantaneous thrust was 32N. When the pulsejet was running on different fuel–air equivalence ratios, the working frequency was different. The load-cell was proved to be capable of detecting and recording each combustion events; and the operating frequency could be derived from the thrust data with high accuracy.