Evaluation techniques for optical analysis of hybrid rocket propulsion

Petrarolo, Anna; Kobald, Mario

doi:10.1299/jfst.2016jfst0028

Cited by 22 publications

(6 citation statements)

References 33 publications

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“…12,13) Theoretical frequencies and wave-lengths of this entrainment process are evaluated in 12) and are compared with experimental results in. 14) Scale-up tests were done and confirmed that the theory is also applicable for engines at larger scale. 15) Recent tests with different Paraffinbased fuels and Gaseous Oxygen (GOX) showed an exponential relation between the liquid layer viscosity and the overall regression rate.…”

Section: Liquefying Hybrid Rocket Fuelsmentioning

confidence: 61%

A Record Flight of the Hybrid Sounding Rocket HEROS 3

Kobald¹,

Schluechter²,

Fischer³

et al. 2018

AEROSPACE TECHNOLOGY JAPAN

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Hybrid rocket propulsion offers inherent safety during handling and launch operations at low cost. This makes it not only attractive for space tourism applications like SpaceShipTwo but also for sounding rockets and for educational activities with students. This has been successfully demonstrated by the HyEnD student project from the University of Stuttgart: On November 8 th , 2016 at 10:30 a.m. the hybrid sounding rocket HEROS 3 was launched from the Esrange Space Center to an apogee altitude of 32,300 m (106,000 ft). This set a new altitude record for European student and amateur rocketry. Furthermore, this is a world altitude record for hybrid rockets built by students. It was successfully recovered with the drogue and main parachute being released. The rocket was powered by a 10 kN design thrust hybrid rocket engine with a paraffin-based fuel and Nitrous Oxide (N 2 O) as the oxidizer. The combustion efficiency was verified to be above 97 % in ground tests. Liquid burn time in the flight was for 15 s with an additional combustion of gaseous N 2 O in the blow-down mode of about 10 s. The rocket was 7.5 m long with an empty mass of about 75 kg. The rocket structure was made completely from light-weight carbon fibre and glass fibre reinforced plastic.

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Section: Liquefying Hybrid Rocket Fuelsmentioning

confidence: 61%

A Record Flight of the Hybrid Sounding Rocket HEROS 3

Kobald¹,

Schluechter²,

Fischer³

et al. 2018

AEROSPACE TECHNOLOGY JAPAN

Self Cite

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“…A test sequence is programmed before the test and is run automatically by the test bench control system. More details about the test bench and test settings are given in Kobald et al (2015), Petrarolo and Kobald (2016), Petrarolo et al (2018).…”

Section: Combustion Testsmentioning

confidence: 99%

Local anomaly detection in hybrid rocket combustion tests

Rüttgers

Petrarolo

2021

Exp Fluids

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Local anomaly detection was applied to image data of hybrid rocket combustion tests for a better understanding of the complex flow phenomena. Novel techniques such as hybrid rockets that allow for cost reductions of space transport vehicles are of high importance in space flight. However, the combustion process in hybrid rocket engines is still a matter of ongoing research and not fully understood yet. Since 2013, combustion tests with different paraffin-based fuels have been performed at the German Aerospace Center (DLR) and the whole process has been recorded with a high-speed video camera. This has led to a huge amount of images for each test that needs to be automatically analyzed. In order to catch specific flow phenomena appearing during the combustion, potential anomalies have been detected by local outlier factor (LOF), an algorithm for local outlier detection. The choice of this particular algorithm is justified by a comparison with other established anomaly detection algorithms. Furthermore, a detailed investigation of different distance measures and an investigation of the hyperparameter choice in the LOF algorithm have been performed. As a result, valuable insights into the main phenomena appearing during the combustion of liquefying hybrid rocket fuels are obtained. In particular, fuel droplets entrained into the oxidizer flow and burning over the flame are clearly identified as outliers with respect to the main combustion process. Graphic abstract

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“…A test sequence, reported in Table 1, is programmed before the test and is run automatically by the test bench control system. More details about the test bench and test settings are given in Kobald et al (2015); Petrarolo and Kobald (2016); Petrarolo et al (2018).…”

Section: Combustion Testsmentioning

confidence: 99%

“…For this reason, a comparison of the outcome of different clustering algorithms on a two-or three-dimensional representation of test 284 is performed since the test can be better visualized then. In Petrarolo and Kobald (2016), the experimental dataset is reduced in complexity with classical decomposition techniques such as a Principal Component Analysis and an Independent Component Analysis. In this study, an approximation based on image moments is used, as shown in Fig.…”

Section: Adequate Choice Of Clustering Algorithmmentioning

confidence: 99%

Clustering of paraffin-based hybrid rocket fuels combustion data

2019

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Clustering was applied to image data of hybrid rocket combustion tests for a better understanding of the complex flow phenomena. Novel techniques such as hybrid rockets that allow for cost reductions of space transport vehicles are of high importance in space flight. However, the combustion process in hybrid rocket engines is still a matter of ongoing research and not fully understood yet. Recently, combustion tests with different paraffin-based fuels have been performed at the German Aerospace Center (DLR). For a detailed analysis, the combustion process has been captured with a high-speed video camera, which leads to a huge amount of images for each test. In the end, a large dataset with a total number of 30 000 images for each combustion test has to be analyzed. In order to catch the essential flow structures, the combustion dataset was clustered with a K-means++ algorithm. Since the algorithm might converge to local optimal solutions, expensive repetitions have been performed in order to ensure that a global

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Evaluation techniques for optical analysis of hybrid rocket propulsion

Cited by 22 publications

References 33 publications

A Record Flight of the Hybrid Sounding Rocket HEROS 3

A Record Flight of the Hybrid Sounding Rocket HEROS 3

Local anomaly detection in hybrid rocket combustion tests

Clustering of paraffin-based hybrid rocket fuels combustion data

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