Aerodynamic Optimization of Turbine Based Combined Cycle Nozzle

This paper aims at optimizing a Turbine Based Combined Cycle (TBCC) nozzle for upgrading its aerodynamic performance in multiple flight conditions. An in-house RANS solver called NSAWET is employed for aerodynamic evaluation. The optimizer is a differential evolution algorithm combined with a response surface. Firstly, a two-dimensional model of the initial TBCC nozzle system is investigated. The flow field of the nozzle contains complicated shockwave interactions that cause thrust loss. Then multi-point aerodynamic optimization of a two-dimensional ramjet nozzle is carried out, which objectives are to maximize the thrust coefficients at Mach numbers 2.5, 3.0 and 4.0. The objective functions are increased substantially at the first two Mach numbers after optimization, while slightly decreased at the last Mach number. The turbine flow path is built up based on the optimized profile and the performances in typical flight conditions are validated. Results demonstrate that both the ramjet and turbine nozzles are improved in most flight conditions.

Efficiency calculation on 10 MW experimental steam turbine

The paper deals with defining flow path efficiency of an experimental steam turbine by using measurement of flow, torque, pressures and temperatures. The configuration of the steam turbine flow path is briefly described. Measuring points and devices are defined. The paper indicates the advantages as well as disadvantages of flow path efficiency measurement using enthalpy and torque on the shaft. The efficiency evaluation by the help pressure and temperature measurement is influenced by flow parameter distribution and can provide different values of flow path efficiency. The efficiency determination by using of torque and mass flow measurement is more accurate and it is recommended for using. The disadvantage is relatively very complicated and expensive measuring system.

Optimal Design of Gas Turbines Flow Paths Considering Operational Modes

A new technique for multi-parameter optimization of gas turbines flow paths considering a variable mode for their operation is presented. It allows the estimation of the influence of flow path optimization on performance parameters of gas-turbine units, such as power, efficiency, and fuel consumption. An algorithm for turbine flow path multi-criteria optimization that takes into account the gas-turbine unit operation mode is shown. Approaches to speed up the optimization process are described. Using this technique GT-750-6M low pressure turbine flow path optimization based on real working loads during one year is carried out and the results are analyzed. Due to optimization the unit efficiency was improved at all operating modes. The total fuel economy for considered period makes 50.831 t.

Research on Multidisciplinary Design Optimization of Aeroengine Turbine Flow Path in the Preliminary Design Phase

The design of an aero-engine is traditionally divided into three levels: conceptual design, preliminary design and detailed design. This three-step design process is inherently iterative, which can slow the design process and overall productivity. Additionally, as an integrated systems engineering analysis, aero-engine design involves multiple-disciplines. The complex coupled-relationship among multiple-disciplines and multiple-components gives rise to severe conflict with performance requirements when designing, especially when it comes to high-performance aero-engine. Traditionally, designers need to empirically balance all kinds of requirements, which lead to a longer design cycle. So it is necessary to apply Multidisciplinary Design Optimization (MDO) to organize and manage the process of design system which sufficiently utilizes the effect of interaction of multidisciplines for the optimal solution. The MDO of a turbine flow path is one of the key multidisciplinary optimization technologies in aeroengine overall design. The problem studied and presented in this paper consists in optimizing a turbine modeled by a multidisciplinary system of two coupled disciplines: turbine aerodynamics and structural strength, with temperature limited by the materials. In the present work, three modules are established to conduct the MDO research of turbine flow path: flow path design, turbine strength calculation and MDO. The aeroengine turbine flow path, including high and low pressure turbine flow path, is designed in the first module, with its efficiency estimated. In the second module, turbine rotors consisting of blades, discs and the low spool shaft are parametric modeled so as to analyze the structural aspects of turbine rotors, such as weight and stresses. MDO is conducted using multi-island genetic algorithm optimization (MIGA) optimization algorithm provided in iSIGHT software. Fully Integrated Optimization (FIO) strategy is studied to deal with the multidisciplinary analysis. The complex coupling relations between aerodynamic performance and turbine strength are analyzed to establish turbine multidisciplinary optimization system. The optimal values of loading coefficient, rotational speed, bore diameter of rotor discs defined by the shaft size, and other independent design variables are obtained in order to achieve minimum weight of turbine rotors while simultaneously meeting the strength and aerodynamics efficiency requirements. This method presented in this paper can greatly shorten turbine design cycle, improve aeroengine design ability, and is prospective to be widely applied to engineering field.