the design of a hybrid rocket engine - AURA - Alfred University

In this thesis, a hybrid rocket engine is designed and built to experimentally test different materials that can be used as fuel. Disadvantages of using ABS include its low melting point, which produces lower thrust, and it burns faster than traditional hybrid rocket fuels.

Background on Rockets

Liquid Rockets

Solid Rockets

Hybrid Rockets

The Advantages of Hybrid Rockets

History Of 3D Printing

He worked for a company called 3D Systems Corp™ where he researched and produced his 3D printer.

How 3D printing is Used

The Makerbot™

The end result of the hybrid rocket stand design can be seen in the figure below. This resulted in the load cell never zeroing due to the weight of the grain and end plates. Once this transformation of the shape took place, the material was ready to experiment with in the 3D printer.

The amount of aluminum used in the total material was approximately 10% of the ABS weight. However, the filament extruder did not always produce an ABS/Al mixture that could be placed in the head of the 3D printer. The material entered the head of the 3D printer and was transported to the nozzle, where it began to melt.

When the procedure failed, material hardened in the head of the 3D printer, as before. The first step taken to get the 3D printer to print was to enlarge the port in the nozzle. The largest half of the material was placed in the SEM broken side up.

Place a new O-ring into the O-ring groove at the top and bottom of the grit. Then select 'Load Filament' and carefully place the new ABS/Al filament into the head of the 3D printer.

Background On Hybrid Rocket Research

How This Research Will Improve Hybrid Rockets

Thesis Statment

Regression Rates

The regression rate is controlled by turbulent heat and mass transfer in the reacting boundary layer. The following figure is an average regression rate comparing two rocket grains of two different materials.

Figure 7. Fuel regression rate in different size motors. 2

Heat Transfer

Additionally, the complication in a hybrid rocket engine is that the vaporizing/liquid fuel leaving the surface of the grain significantly reduces the rate of heat transfer from the surface. This mechanism significantly increases the rate of fuel mass transfer, leading to a much higher regression rate than can be achieved with conventional polymeric fuels by a factor of three to five.3 This can be seen in the following figure.

Characteristic Velocity

As shown in the figure above, the mass burning rate for HTPB at 13% is Alex®. aluminum) is higher than pure HTPB. However, it is believed that as the mass burning rate increases, the regression rate will also increase.

The Rocket Stand

Designing and Constructing The Stand

After the end plates were designed and machined in the CNC, the frame of the rocket stand was simple. Finally, the valve that lets the oxygen from the regulator into the rocket's combustion chamber is opened. All the drawings for each part of the extruder can be viewed further in the appendix.

The positive terminal from the power supply had to be wired to the positive terminal of the motor. The port on the 3D printer head was spaced to allow 1.75mm ABS filament to be printed through. After the new ABS/Al material was extruded, it was then examined under SEM to assess the aluminum distribution.

If the aluminum were combined in one piece of plastic, the material would not burn evenly when fired into the rocket.

Testing Procedure

The Impovements Made On The Stand

Hybrid Rocket Fuel

The Combustion of ABS+O 2
The Instrumentation
Comparing Results Of Different Fuel Designs
Designing ABS Grains
Operator Procedure For The Makerbot

The figure shown below is one of the LabVIEW™ programs written to measure the force and pressure distributed by the rocket. Part of the experiment with the hybrid rocket was to see how the ABS grains would perform as a propellant. The basic grain and the results of the grain when melted can be seen in Fig.(26).

The spiral shape and the O-ring were the two characteristics of the pellets that were focused on when they were designed. The bottom of the O-ring groove was 0.14 inches and the small radius used on the corners was 0.02 inches. Move the grain to the center of the platform and set the part of the.

Take the SD card that has the G-code on it and insert it into the slot on the left side of the Makerbot™.

Figure 23. The thermal camera capturing the rocket.

The Design

Lyman Filament Extruder

Budget Comparison

When all the parts that went into its design were estimated, the final cost of the Lyman Filament Extruder was $560.16. When the price of the filament extruder used for this project was reduced to $42.38, less than 1/10 of the price.

The Circuit Diagram

The Procedure

Pre-Set-Up

Procedure

The material did take some time to heat up enough to soften enough to exit the nozzle. However, after waiting a few minutes, the material slowly began to leave the port of the nozzle. Once the material started coming out of the nozzle faster, all that was left was to pop the new filament out of the nozzle and let gravity pull the filament together.

Clean Up

Preparing the Plastic/Aluminum

Selecting The Adequate Acetone/ABS Mixture

The Procedure Of Weighing Aluminum

There was no guarantee that the filament extruder would work once the aluminum was added to the ABS/acetone mixture. The solution to these problems was to make different concentrations of aluminum in the mixture. Since the goal of this project was to be able to combine 3D printing with ABS and 10% of aluminum, this was the first concentration that was tried.

In that equation MAl was the mass of aluminum and MABS was the mass of ABS plastic. To begin this procedure, the first step was to weigh a 76.2 cm (30 in) piece of ABS filament as seen in the figure below. A balance made by Denver Instruments was used to weigh 76.2 cm (30 in) of ABS and aluminum nanoparticle.

Procedure Of The ABS/Aluminum

It was removed from the beaker and, using scissors, cut into pieces small enough to fit into the hopper of the filament extruder. Once the ABS/Al was in the form of small chips, it was ready to be used in the filament extruder.

The ABS/Al Processing

The Extruded Material

The next step was to get the Makerbot™ to 3D print the new material, and the only way to do that was to eliminate the breast on the filament. The best solution to solving the drill problem was to take a piece of 600-grit ultra-fine sandpaper and carefully sand down the drill. Once all the bristles were off the filament, the 10% aluminum material was successfully placed into the head of the 3D printer.

Experimentation with the Percentage of Al in the ABS

An important part that was noticed when experimenting with this material was that it did not clog the MakerBot™ head.

Difficulties with the Results

Adjusting the 3D Printer

How to Use the Filaments in the Makerbot™
How to Clean the Head of the Makerbot™
Port Sizes vs Speed vs Temperature
Results from the 3D Printer

While experimenting with different filaments that had different aluminum concentrations, some of the filaments would not release from the Makerbot head. When the aluminum nanoparticles were added to the plastic, the melting point had to rise to the point where the current temperature of the 3D printer nozzle was not hot enough to soften the material. The next area to look into was the 3D printer port sizes, speeds and temperatures.

These experiments were intended to increase the heat of the nozzle, increase the port size of the nozzle, and decrease the feed rate of the 3D printer. The temperature was defaulted to 220 degrees Celsius, the feed rate was 50 millimeters per second, and the original size of the port in the nozzle was 0.007 of an inch. The initial size of the port was extremely small. about 0.005 of an inch, and easily plugged.

When the temperature was set to 230, the ABS/Al came out of the port in small conglomerates.

Figure 56. New material being 3D printed.

SEM Analysis

SEM Before the Filament was 3D Printed

SEM was performed on the filament before it was 3D printed in a 3D printer at various stages. After it was melted, it was extruded in a manufactured filament extruder. Once the ABS and aluminum were placed together, they were prepared differently before being scanned in the SEM.

The figure below shows the ABS/Al blend in SEM after the material has been polished. To polish a material for use in SEM, the material must first be ground and polished. This was done to see how much aluminum remained in the material after it was extruded.

It also shows how when the aluminum is dissolved in the ABS, it is distributed in different amounts.

SEM After the Filament was 3D Printed

The chemical analysis result was performed only shows that there is still aluminum in the material after it was 3D printed. It only gives a quantitative amount of a small part of the substance from the upper layer. A spiral pattern in the combustion chamber was created in an attempt to increase the efficiency of the rockets thrust.

Some of the parts to make the filament extruder were a band heater, a PID controller, a wiper motor, and a nozzle. Another area that still needs research is the SEM figures of the new material. The final key would be finding a polymer scientist who could take a piece of the new material and generate a new one.

Tighten the bolts back into the rocket and take the rocket to the test platform. Before the new material can be 3D printed in the Makerbot™, the ABS filament already in the printer's head must be released and the new material being experimented on must be placed in place. Once this is all complete, the motor in the head of the 3D printer, which moves the filament through the head, reverses and releases the filament.