Vibration test for 7 ton-class liquid propellant rocket engine

Paper number

IAC-19,C2,IP,9,x53091

Author

Dr. Jinhyuk Kim, Korea, Republic of, Korea Aerospace Research Institute (KARI)

Coauthor

Mr. Jong Youn Park, Korea, Republic of, Korea Aerospace Research Institute (KARI)

Coauthor

Dr. Jun Young Kwak, Korea, Republic of, Korea Aerospace Research Institute (KARI)

Coauthor

Dr. Jae Han Yoo, Korea, Republic of, Korea Aerospace Research Institute (KARI)

Coauthor

Dr. Yoonwan Moon, Korea, Republic of, Korea Aerospace Research Institute (KARI)

Coauthor

Mr. Indeuk Kang, Korea, Republic of, VMV-TECH

Coauthor

Mr. Iksung Choi, Korea, Republic of, VMV-TECH

Year

2019

Abstract

7 ton-class liquid propellant rocket engine is newly developed for Korea space launch vehicle II (KSLV-II). The engine is mounted on the upper stage of the launch vehicle and is exposed to various dynamic loads during the combustion of the first stage engines. Under the new engine development, it is very important to know dynamic characteristics of the engine and to guarantee its structural integrity against the dynamic loads. In this regard, the vibration tests are taken into consideration under the current engine development program. This paper will present the vibration tests of the new engine, which mainly focused on the modal test and dynamic environmental test.
In the modal test, the dynamic characteristics of the major components such as combustion chamber, turbo-pump, load-bearing structures, brackets, and pipe lines were obtained from the impact hammer test and shaker modal test. In sub-assembly level, the boundary conditions and dynamic characteristics between the assembling components were extracted and were updated to the analysis model for the correlation between the test results and analysis results. Natural frequencies, mode shapes, and damping of the engine were obtained from the modal test. The analysis results from commercial software were successfully correlated with the test results.
In the dynamic environmental test, the structural integrity of the engine against the low frequency dynamic loads was verified through the sine vibration test. The test specification was estimated from the full-scale load analysis and actual flight data of the launch vehicle. The specified input level was notched to prevent overtesting problem caused by the difference in conditions between the flight and vibration test. Dozens of accelerometers and strain gauges were installed to the critical locations of the engine to obtain its structural responses related to the dynamic characteristics and structural integrity. After the environmental test, the tested engine was examined to verify its structural integrity and operability. Several tests such as leak test, valve operation test, and sensor signal test were conducted on the tested engine. The tested engine met all examining requirements after the environmental test.
In this study, the vibration tests were successfully conducted on the newly developed engine. The test results and updated analysis model will be used as important information for current engine improvement and next generation engine development.

Abstract document

IAC-19,C2,IP,9,x53091.brief.pdf

Manuscript document

(absent)