Rocket motors are flow machines and flow machines are sensitive to flow dynamics. In other words, the physical-chemical processes of rocket engine are sensitive to propellant total flow and the propellants flow ratio, so the flow measurement is crucial not only for the rocket engine characterization but also it is essential in performance calculations. Therefore the reduction of uncertainty of flow measurement has a significant impact on the quality of the final results of rocket engines tests, especially in measures of performance parameters: Specific Impulse (Is) and C-star (C*).
Perhaps one of the more unique applications for Micro Motion Coriolis flowmeters is their use in a rocket engines test stand. The presenter, André Prado of the Instituto de Aeronáutica e Espaço described the rocket portfolio from smaller ones to very large ones for launching satellites into geosynchronous orbit.
Andre showed a video showing the components of the rocket and its solid fuel engine. They needed to test and simulate all the dynamics associated with the launch to verify the performance and interactions of the components. The rocket attains a speed of 7000 meters per second when it releases the satellite payload.
He showed a second video with a number of rocket explosions. These tests are very expensive and thus necessitated the need to manage the flow of the fuel and oxidizer which ignites the fuel and produces the thrust. Two ways to increase the thrust are to increase the fuel flow rate and increase the exhaust velocity.
Andre shared the equations involved in thrust. If you are attending the conference and access his presentation, you can get on the path to becoming a rocket scientist in your own right!
The rocket engine have separate fuel tanks and oxidizer tanks that feed into the combustion chamber. Control valves control the lines into the combustion chamber. More complex designs include pre-burners for staged combustion.
Almost all the rocket engines components require flow measurement in the tests to verify their performance and that they meet the design specifications. A cold test stand pretests the rocket elements and identifies their general behaviors. The second step is a hot test stand to identify the dynamic behavior of the thrust chamber and provide measurements of performance.
Micro Motion Coriolis flowmeters were used to measure since other technologies such as magmeters, vortex, orifice plates/differential pressure, The measurement had to be fast to allow readings in 4-second time windows. The other flow measurement technologies could not react that quickly. Pressure drop across the meter was also lower than the other technologies. Micro Motion mass flow meters could accurately measure the fuel and oxidizer flows in these small time windows. The key was the Micro Motion reduced measurement uncertainty by a 1/2%. But given the massive fuel and oxidizer flow rates over an extremely short time window, this uncertainty significantly impacted the thrust calculations. The reductions allowed the testing to more accurately predict the performance of the rocket when launched.
Andre summed it up–better flow measurements = better test results, more efficient components, more efficient rocket engines, and greater confidence of successful launches.