![]() Compared with first-stage rocket engines, space engines have lower chamber pressure and smaller size, so their nozzle efficiencies are lower. Their research reveals that increasing chamber pressure leads to an increase of nozzle efficiency and that the kinetic losses raise up to 1% at lower chamber pressure. Manski and Hagemann studied the influence of rocket design parameters on nozzle efficiencies using the nozzle shapes of SSME and Vulcan engines. The efficiency of a rocket nozzle is affected by many parameters. In contrast, increasing the nozzle efficiency is more effective. However, it is hard to increase the combustion efficiency because higher combustion efficiency means higher combustion temperature, which increases the risk of failure of material or coating system. To achieve this goal, we can increase the combustion efficiency or nozzle efficiency. įor a space engine, to improve the specific impulse is still the goal of engine design because the higher specific impulse means a longer life cycle. For example, S400-15 has the specific impulse of 321 seconds at the nominal point, R-4D-14 (HPLAE) has demonstrated a specific impulse of seconds, and the of China’s second-generation 490 N apogee engine is 315 seconds. The vacuum specific impulse ( ) of apogee engines is usually above 300 seconds. IntroductionĪ de Laval nozzle of large area ratio is generally used in the rocket engines for space propulsion, such as apogee rocket engines that use hypergolic bipropellant combinations. The extension curve bent outward with increasing expansion angle increases the vacuum specific impulse obviously. For the space engine, a new extension contour type for the end section of the nozzle is proposed. The expansion contour designed by this method has much thinner expansion section and higher performance. A simple modification of Rao’s method based on thermally perfect gas assumption was made and verified to be more effective. The calculation results show that increasing the heat capacity ratio can produce an expansion contour of smaller expansion angle and exit area ratio. This paper analysed the effect of the constant capacity ratio in Rao’s method through the design process of an apogee engine. The nozzle efficiency is greatly affected by the nozzle contour. or the modal approach in the flow solver that takes advantage of the harmonic solution of the NLH method and solves the modal equations, to compute the global deformation of the structure written as a composition of mode shapes, removing the necessity of interpolation between fluid and solid domains.A rocket engine for space propulsion usually has a nozzle of a large exit area ratio.the use of the coupling server MpCCI, which manages the communication and the interpolation of coupling data between the fluid and structure solvers,.the direct coupling between the flow and the structural solvers,.Cadence offers several approaches to predict fluid-structure interactions depending on: A continuous trend towards lightweight and cost-efficient design forces engineers to push the boundaries in the design phase with the risk of leading to vibratory stresses and, in the worst case, to vibratory failure. The significance of aeroelastic instabilities has increased substantially in the last few decades, particularly in the industry of aviation and turbomachinery. This method is 2 to 3 orders of magnitude faster than a classical URANS simulation.įluid-Structure Interaction (FSI) occurs when a fluid flow deforms a structure which in return influences the flow field. The Nonlinear Harmonic method is used to model the unsteady interaction between the blade rows as well as the influence of the non-homogeneities at the combustor outlet on the downstream turbine blade rows. While the approach is superior to classical tabulated chemistry approaches and reliably captures finite-rate effects, it is also computationally inexpensive. One of the advantages of a fully coupled approach over a component-by-component approach is that the boundary conditions at the interfaces do not need to be guessed.Ī Smart Interface methodology ensures a direct coupling between the different engine components, compressor- combustor-turbine, and allows the CFD models to vary between each component within the same CFD code.įor the simulation of the combustion process, the Flamelet Generated Manifold (FGM) method is applied. With the purpose of meeting future aircraft engine requirements in terms of low emissions, high reliability and efficiency, a novel highly efficient fully-coupled RANS-based approach has been developed, enabling the simulation of a full aero-engine within a single code.
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