Optimizing Fuel Composition for Thrust in Pulsejet Engines

Overview

Pulsejet engines offer an exciting avenue for research due to their simple design and unique combustion cycle. This study investigates how varying fuel compositions of propane and butane impact thrust performance in a small -scale pulsejet engine. The hypothesis posits that 100% propane, due to its higher vapor pressure and ease of ignition, would outperform other mixtures in thrust output. Experiments were conducted using a custom -built pulsejet engine and a precision thrust measurement rig. Three fuel compositions were tested: 100% propane, 100% butane, and a 70:30 mixture of butane and propane. Each configuration underwent three trials, an d thrust was measured in grams. Results showed that 100% propane generated the highest average thrust at 320 grams, followed by the propane-butane mixture at 285 grams. 100% butane, while offering a higher energy density, produced the lowest average thrust at 250 grams due to its lower vapor pressure and reduced combustion efficiency. These findings confirm that fuel composition significantly influences the performance of pulsejet engines. Propane's properties made it the most effective for consistent thrust, while the propane- butane mixture demonstrated a balance of efficiency and energy output. Butane’s limitations in ignition readiness affected its performance, though its energy density suggests potential benefits in specific scenarios. This study provides insights into optimizing fuel choices for pulsejet applications. Future work could explore advanced designs to reduce variability and examine the impact of ambient conditions on engine performance, contributing to the broader understand ing of pulsejet propulsion.

Competition history

• JSHS 2025 Category not listed

Resources

• National JSHS abstract book ↗

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