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Progress Report Document

Progress Report I

Experimental Design Overview

During the first month of the last semester, we focused on conceptualizing new ideas and refining existing ones. During this month, we drew inspiration from and reviewed science fair projects from previous International Science and Engineering Fair (ISEF) competitions to establish a baseline for research ideas. We were able to come to agreement on a general idea of rocket propulsion and entry into celestial bodies. As we reviewed primary literature and articles related to our topic, we continuously refined and adjusted our project idea. Through our readings of primary literature, we developed a better understanding of the feasibility of entry, its constraints, and identified gaps in our existing research on various rocket nozzles. From there, we shifted our focus to developing a novel geometry specifically for high-pressure atmospheres. Over the months of September to November, as we deepened our understanding of rocket nozzles, we were able to refine our procedure and outline the necessary steps to create our new design while completing all the necessary forms for science fair. To preserve our ideas, around this time we created a multitude of documents with information and ideas relevant to our project. While our topic idea stayed consistent, we subtly tweaked specific areas of our research given what we knew but our procedure stayed relatively the same. For example, we could modify the celestial bodies we simulate, adjust how we rank the nozzles, select the rocket and rocket fuel, and fine-tune minor variables in our equations. After submitting project approval forms, and our proposal we swiftly worked on an order form and reviewed science fair regulations. As we started to finalize our research proposal and methodology we would start working on our research notebook, additional supporting documentation, and our website through the weeks of November through early December. Near the middle of December prior to winter break all of us understood what needed to be completed in the subsequent weeks to finish our project on time.

Experimentation

During the first weeks of January, we conducted hand calculations for bell and conic nozzles. However, due to time constraints, we decided to postpone the calculations for the expansion ratio of the aerospike, given its complexity and the time it required. The hand calculations were used to determine the expansion ration between the throat and the exit region of the nozzle. The expansion ratio is crucial, since it depends on the celestial body due to their difference in pressure and environment, meaning we would need to repeat these calculations to get a proper variance in expansion ratios to maximize thrust efficiency. To solve these equations, we used the interface Desmos and retrieved data from rocket manufacturers or space agencies. We then utilized NASA software, namely their CEA interface, to calculate fuel-based variables such as gamma for hand calculations. To complete the calculations, we used a variety of data from many reputable agencies including NASA and SpaceX and rechecked over our calculations thoroughly and sensibly, taking us two weeks. During this time, Rocket Propulsion Analysis (RPA) software was crucial in generating 2D contours of the nozzles we designed, including the bell nozzle model for Titan (Figure 1). After completing these calculations, we gained a better understanding of how to later approach the complexity of aerospike hand calculations, and we are currently analyzing their deviations. However, we will be unable to complete them before the February science fair deadline, focusing solely on the bell and conical designs for now. After determining the expansion ratios, we calculated the specific length and thickness of the nozzles to compute the nozzle contours and shape. The length can be computed using the L-star table which is dependent of the fuel we used. Currently, we are computing the contour geometries of the nozzle and meshing them using Ansys fluent to run simulations in the following days. We are also printing 3D nozzles in order to display the nozzle for the physical science fair.

Progress Report II

After running Rocket Propulsion Analysis (RPA) software which generated the contour we were then ready to import the contour in fusion and export the geometry into ansys. In Ansys we followed the parameters from videos and research papers doing similar projects. A variety of parameters were inputted to increase accuracy for finer edges and to replicate the environment of each celestial body and external conditions. We ran thousands of testing iterations using the k-epsilon viscosity model for each nozzle on Earth, Saturn, and Titan. Turbulence was also added to model real-world variability. We were then able to collect data in continuity, x-velocity, y-velocity, energy, k-epsilon, and generate Mach number diagrams to model flow. After doing a lengthy data analysis we were able to retrieve figures of the exit velocity while also determining the efficiency. For our results we found, Comparatively the conical rocket nozzles (exit velocities of 1424.54639 m/s and 1240.79578 m/s for Earth and Saturn, respectively) bell nozzles had greater exit velocities in Earthen and Saturnian atmospheric conditions (1428.14978 m/s 1284.5293 m/s, respectively). When simulating Titan's atmosphere, the conical rocket nozzle (exit velocity of 1424.54639 m/s) had a higher exit velocity than that of the bell nozzle (1374.72668 m/s). The peak velocities of the conical nozzles were equal to their exit velocities, while the bell nozzles' peak velocities were 1480.76965 m/s, 1478.27051 m/s, and 1284.5293 m/s for Earth, Titan, and Saturn, respectively. Around this time we were also getting ready for the science fair by creating a powerpoint presentation explaining our procedure up until now, a quad chart, and a video which was filmed during class. After a few days we received our results and got first place in the physics category. Then we were notified that some of our forms were filled incorrectly, then we changed that promptly in order to compete in the first phase of the science fair. Presently we have 3D printed the visual displays of the nozzles we have tested, and are currently working on a CAD design for the rocket we based our simulations on, the Falcon 9 Heavy, with the Merlin engine. We have decided going forward, instead of creating a new design and adding a pintle, we plan to explore other geometries of nozzles such as the dual nozzle due to its adaptability in different altitudes. We came to this conclusion by reading literature from Korean teams and literature addressing the aerospike nozzle. We also plan to test these nozzles along different altitudes in order to create discrepancy in results which would help us create an altitude efficient design for high ambient pressures. In order to achieve a new design we would be using Ansys and changing certain parameters, configuring settings, and testing continuously to achieve outright better results. During class, we were also able to figure out what is needed to do Aerospike calculations which we once thought was out of reach. However, given what we know today we might be able to complete these calculations and test this design prior to the first stage of the science fair. Developing a novel altitude adapting nozzle which statistically provides marginal efficiency along with aerospike hand calculations is our new goal. Currently we are required to use Prandtl-Meyer equations along with isentropic flow and thrust equations for creating a contour. However, we are between using Angelino's method or a conventional, simplified way to calculate our contours. Creating an efficient novel design will take a decent amount of time and we fear we will compute a design any time soon.

Progress Report III

During these weeks we focused on turning in the deductibles for the first phase of the Prince William Science fair, our second science fair competition. We filmed our video to give a more comprehensive scope of the challenges we faced during research as advised from Dr. Romano. We would also occasionally go to her office when we had inquiries or wanted advice such as how to approach the video and our quad chart. During these weeks we conducted further background research on the aerospike nozzle, scouring for primary literature for rocket sizing calculations and a new methodology since the geometry of the Aerospike differs from bell and conic nozzles.. Additionally, we used external software developed by MIT graduates to help create a 2D contour for the rocket nozzles. We referenced a variety of primary literature to find specific equations for expansion ratios which fit the variables we already had or needed to compute. We then ran CEA RUN for the specific heat ratios for the aerospike. After calculating the expansion ratio we were able to use the 2D contour software developed by MIT graduates which generates a .txt file of data points and graphs of the contour. The aerospike contour consists of the shroud and the curve. Having complications with exporting the aerospike .txt file to Fusion 360 which is where we generated the full contour and exported the file into Ansys. We had to use the intermediate software, Matlab, which generates a script which calculates essential parameters such as exit Mach number, area ratio, Prandtl-Meyer angle, and flow turn angle using user-specified inputs. Then the program creates a contour in terms of a .csc file which when then were able to upload into fusion. For the next few days we plan to import all .txt into Matlab, and export their .csv file generation into Ansys to develop the 2D contours. This differed from our original methodology which required us to use the software RPA. We have also found primary literature, while background researching for the aerospike helping us with the Ansys setup and meshing.

Progress Report IV

Determining the hand calculations for the aerospike has been very difficult as its shape is abstract from traditional nozzles such as bell and conic. Finding a software which can generate its contour, or export its contour into fusion caused many setbacks and required testing and usage of many external softwares. During our research we came across another nozzle we would be willing to test, namely, the double bell nozzle due to its adaptive performance against overexpansion in high pressure atmospheres. After trying to find an external software to export the aerospike contour into fusion we decided on trying solid works to import the contour and export into a fusion acceptable file. We have tested external software provided by MIT researchers on github, fusion, MATLAB, and even excel to generate an acceptable file for fusion. We were able to generate a contour however with MATLAB, however the issue was determining the exit area of the nozzle, so this idea was overlooked. In the end Anuj clarified the first step should be installing solid works and trying from there. In my opinion, looking for external calculations to determine the exit area would generate better results. Additionally, the exit velocity numerical values are off from the given formulas we received by primary literature making us believe we messed up somewhere along our hand calculation process. Given the secrecy of SpaceX information it is hard to determine whether this is the case or not. We plan to either fix the hand calculations, install solid works and test its capabilities, and do additional research on the dual bell nozzle while completing the online trifold.

Progress Report V

During this time we were able to accomplish many feats in relation to our project. We were thankful to advance to the second stage of the science fair which was held in person. We worked effortlessly to create our project poster and items for our display. The competition was held March 22nd, and from that competition we got 2nd place in the physics category advancing us to the states competition in Piedmont. After the competition we completed the required forms for the state competition, and experimented with the application, solidworks to create a contour to export into Ansys fluent for testing. We were unable to find the area of the exit which was needed for the MATLAB generation of an acceptable Fusion file, so instead we used a github program from a reputable MIT Aerospace engineer with a PHD to generate the data points of an aerospike. At first we experienced problems with inputting the values due to an empty shroud, or glitches along with the software, but after trial and error we were able to display a 2D contour. Although creating a 2D contour was not consistent at all, after refreshing and continual trial and error we would be able to generate this contour for all celestial bodies and will hope to test in Ansys soon. Additionally, we are working on our project poster along with our project, and developing new CAD for the displays and our rocket so it can look more appealing to the judges and audience for the state competition. Going forward we also plan to conduct sensitivity tests, and compile as much data as we could so we can create a novel rocket nozzle.

Progress Report VI

After the science fair we considered the feedback provided from our judges and altered our methodology based on their feedback. We decided to conduct a sensitivity test and re-do the poster to include the contours we plan to create the aerospike. To create the contours we used a python script provided by a colleague at MIT. The script generated a 2D text file of the contour data points and was imported into solid works to create a solid part. In order to use solid works we were forced to create an education account and use its free trial, therefore we had to use Fusion 360 to give the contour faces and export into Ansys. We conducted experimentation on the aerospike using Ansys, however we ran into technical difficulties. Due to the geometry and curves of the aerospike, we were unable to section off the aerospike for testing and biasing. Because of this, we were unable to include our aerospike in our poster for the state science fair. Meanwhile, we 3D printed new display items and a rocket to look more appealing to judges. Throughout the weeks, we conducted a sensitivity test to help us determine which variables affect the expansion ratio of the nozzle. We found that the specific heat ratio also known as the adiabatic index had the greatest effect on its expansion ratio. The sensitivity test will help us develop and optimize a new nozzle which is the scope of our project. At the Virginia Science and Engineering Fair we were able to come in the top five of all the projects at the fair securing an honorable mention award. Moreover, we were also we were notified that we won an organization award at the American Institute of Aerospace and Aeronautics (AIAA) and our VJAS paper was accepted and we were invited to the in-person fair.

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