Аuthors

Kartovitskiy L. L.^*, Yanovskiy L. S.^**

Central Institute of Aviation Motors, CIAM, 2, Aviamotornaya St., Moscow, 111116, Russia

*e-mail: levka_58@mail.ru
**e-mail: yanovsky@ciam.ru

Abstract

During design of ramjet for high-speed vehicle at the stage of firing tests, the task of analysis and estimation of the working process performances is arisen. Using test results, the ramjet combustor design is modified in further developments. However, the direction of modification is largely determined by reliability of some estimations for performances obtained by processing measurements. Usage of methane in an air heater leads to uncertainty for chemical composition in combustion products during firing tests, which is the reason of inadequate between test facility and flight conditions. This creates an uncertainty in the thermodynamics of the flow supplied into tested ramjet and the direct transfer of firing test results to a full-scale object for analyzing of its performances. The article proposes a thermogasdynamic model for estimation of the parameters and impulse of the heater nozzle during firing tests using the scheme of connected supply of heater combustion products with an undefined chemical composition. The thermogasdynamic model is developed on the integral equations of conservation laws and, taking into account the obtained test measurements that allows to construct additional equations by transforming their into a convenient form for evaluating the thermodynamic parameters of the heater combustion products. Using the developed model, comparative calculations of the impulses of the input nozzles for heater in test conditions for design and off-design regimes have been performed. Estimations of deviations for design Mach numbers on average 5% and for output impulse 10% are obtained at condition implementation of the conservation equations with account dependence of the gas-dynamic parameters from current thermodynamic state of the gas flow. Developed thermogasdynamic model let to calculate the correction of heater nozzle geometrical expansion providing the design regimes for Mach number in facility conditions.

Keywords:

Estimation of the nozzle input impulse for air heater during tests of a ramjet

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