The high-loaded centrifugal compressor blisk-type impeller, one of the main low-sized gas-turbine engine components, strongly affects engine efficiency. However, its design is a time-consuming and complex task for several reasons, including its high loading, the large number of structural and technological constraints, and the variety of requirements needed for application to a gas-turbine engine centrifugal compressor impeller (e.g., increased efficiency and strength, minimized weight requirements, etc.). The imposition of several constraints for structure modification of the centrifugal wheels can improve one characteristic but can worsen others. The standard solution for this problem is to use an iterative approach, whereby the design process is reduced to a consistent set of impeller element design problem statements and decisions; these are separate for different analysis disciplines. The main drawbacks to this approach are that it is labor intensive and can cause deterioration of the design quality because this procedure does not consider the design object as a unit. The present work considers a centrifugal compressor wheel design approach based on the use of an integrated multidisciplinary parameterized 3D model. This model includes a number of specialized sub-models that describe the necessary design areas as well as physical process features and phenomena occurring in the designed object. The model also realizes the integration and interaction of sub-models used in an integrated computing space. The proposed approach allows the optimization of the structure based on several criteria, such as the mass of the wheel, stage efficiency, strength, economic indicators, etc. The result of multi-criteria optimization is not a single product design, but a set of optimal Pareto points, which describes a number of centrifugal wheel models. The optimal configuration is selected from this set, based on what is considered the most important criterion. Optimization criteria may vary depending on the problem formulation, but the design technology, parameterization scheme, and choice of multidisciplinary integrated mathematical model are retained. Therefore, in the case of a product requirement correction, a new optimal design will require less time. In aggregate, with the nonlinear constrained optimization application, this approach reduces the total time of the design cycle, decreases development costs, and improves quality.

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One of the most important units of small-size gas-turbine engines (GTE) is a turbine bladed disk, since it determines the total engine efficiency. Designing a turbine disks is a complex challenge due to the high loads and a large number of structural and technological constraints, as well as a variety of requirements to the bladed disks for small-size GTEs (higher efficiency, lower mass and adequate strength characteristics, etc.). Diverse requirements to the turbine bladed disks mean that modifying the structure in order to improve some characteristics will degrade other characteristics. A standard solution to this problem is to use the iterative approach, which reduces the design process to a consecutive iteration of setting and solving design problems concerning the bladed disk elements (blade and disk) separately for different aspects. The main drawback of this approach is its tremendous labor intensity and inferior quality of design, as this procedure does not consider the design object as a single entity. This paper proposes an approach to the turbine bladed disks design based on the use of a single multidisciplinary parametrized 3D model that contains several specialized submodels. These submodels define the essential computational regions, as well as the characteristics of the physical processes and phenomena in the object under study. The model also enables integration and interaction of the submodels in a single computational region. The single multidisciplinary model is modified and analyzed automatically, so the design problem is transformed into a multi-criteria optimization problem where the weight, gas dynamic and strength characteristics are used as criteria or constraints, and they are improved by varying the geometric parameters of the blade and disk. Each submodel simulates and analyzes the essential characteristics at the level comparable to the standard engineering calculations. Therefore, the designs obtained as a result of optimization do not need significant improvements, which facilitates and enhances the design process. The development of an integrated model is time consuming, but since the design and operation of bladed disks are similar, the created parametrized multidisciplinary 3D model can be used in the design of other similar disks after minor alternations taking into account the specifics of the new task.

Restrictions of emissions for civil aircraft engines, on the one hand, and the need in increasing the engine efficiency, on the other hand, cause difficulties during development of low-emission combustors for such engines.

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