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1

Cavitating Venturi as a Mass Flow Controller in a Deep Throttling Liquid Rocket Engine

Sekrecki Michał

Transactions on Aerospace Research

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2023

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Nr 3 (272)

72--86

EN

The most common solutions for rocket engines are the single operation point (thrust level) units. Oxidiser and fuel mass flow rates and the oxidiser-to-fuel mass flow rate ratio (OFR) are some of the determinants of the thrust level. Based on these, planetary ascent and descent; space rendezvous; orbital manoeuvring, including orientation and stabilisation in space; hovering, hazard avoidance during planetary landing; and ballistic missile trajectory control propulsion systems could use throttleable liquid engines. Several engine throttling methods, such as supply pressure variation and variable injector area, can be applied. Among others, a cavitating venturi propellant regulatory valve is one of the most promising throttling method. This type of valve can provide steady mass flow, despite the downstream pressure disturbance (i.e. from the combustion chamber), which sustains a stable engine thrust as the mass flow is kept. The article presents the valve sizing method, design and prototype test results of the cavitating venturi valve that has potential for utilisation in a deep throttling rocket engine. Mass flow stability and repeatability are presented for valve operating points in the 10%-110% nominal mass flow range. Valve design optimisation, based on CFD, to sustain cavitation for a higher downstream-to-upstream pressure ratio is shown.

2

The emission and combustion characteristics of marine diesel engine with extreme throttled of air or exhaust ducts

Kowalski J.

New Trends in Production Engineering

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2018

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Vol. 1, Iss. 1

427--433

EN

Presented paper shows the results of the laboratory tests on the relationship between the extreme throttling of both air intake duct and exhaust gas duct and gaseous emission from the marine engine. The object of research is a laboratory, 4-stroke, DI diesel engine, operated at loads from 50 kW to 250 kW at a constant speed equal to 750 rpm. During the laboratory tests the thermodynamic and exhaust gas emission characteristics of the engine were measured with technical condition recognized as "working properly" and with simulated throttling of both air intake duct and exhaust gas duct. Air intake duct throttling by 60% causes visible changes at both gas temperature and pressure behind the intercooler. The study results show significant changes of NOx and CO2 emission for considered air intake duct throttling. The best indicator of exhaust gas duct throttling among considered thermodynamic parameters of the engine is mean in-cylinder pressure. In the case of measuring the composition of exhaust gas, the throttling of the exhaust gas duct causes visible changes in CO2 and NOx emission. The conclusion is that the results of measurements of the composition of the exhaust gas may contain valuable diagnostic information about the technical condition of air intake and exhaust gas duct of the marine engine.

3

Badania modelowe cylindrycznych regulatorów hydrodynamicznych

Wójtowicz P., Kotowski A.

Ochrona Środowiska

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2008

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Vol. 30, nr 2

35-41

PL

Na podstawie analizy stanu wiedzy z zakresu urządzeń o działaniu wirowym, opracowano metodologię badań modelowych regulatorów wirowych przepływu cieczy do zastosowań w inżynierii środowiska. Przedstawiono wybrane wyniki badań wpływu parametrów konstrukcyjnych (średnica i wysokość komory wirowej, średnica króćca dopływowego i otworu odpływowego), a także eksploatacyjnych (średnica rdzenia gazowego i kąt rozpylenia cieczy) na charakterystykę przepływu regulatorów o cylindrycznym kształcie komory wirowej. Zbadane zależności funkcyjne umożliwiają racjonalny dobór parametrów geometrycznych tych regulatorów. Wykazano, że uwzględnienie parametrów eksploatacyjnych przyczynia się do zwiększenia dokładności opisu współczynnika przepływu badanych urządzeń. Wykazano, że ustalone wzory empiryczne umożliwiają projektowanie konstrukcji takich regulatorów.

EN

Upon analysis of the current knowledge regarding vortex devices, a model test methodology for liquid flow vortex regulators has been developed, which is of practical use in environmental engineering and pollution control. The paper presents a choice of test results elucidating the effect of construction parameters (vortex chamber diameter and height, inlet and outlet diameter), as well as operation parameters (air core diameter and spray cone angle), on the performance of flow regulators with cylindrical vortex chambers. The investigated functional relations enable a rational choice of geometrical parameters for the regulators in question. It has been demonstrated that when the operation parameters are taken into account, the description of the discharge coefficient of the devices tested gains in accuracy. The empirical formulae derived are of support to the designer of the constructions for such regulators.