Gas turbine cost and value management in the conceptual design stage

The development of product concept is a crucial task which cannot leave aside value assessment and product cost management. Value engineering is in charge of ensuring that key operations are performed at the lowest possible cost while still meeting performance, reliability, availability, quality, and safety requirements. This paper aims to describe a systematic approach for comparing design options created during the conceptual design stage of gas turbine components, based on cost evaluation and value analysis. The method allows designers to define design concepts for achieving target costs by combining functional decomposition, conceptual cost modelling, and the Value Analysis Value Engineering (VAVE) method. Functional decomposition allows identifying gas turbine modules and related components providing the main features to develop. Conceptual cost modelling is used as a decision-making design tool to predict the overall cost of gas turbine modules, and VAVE is adopted to find disruptive ideas and design changes whenever the gap between the estimated cost and the target cost is not compliant with the company requirements. The main outcome of the proposed methodology is to anticipate the cost of projects since the very conceptual stages with an acceptable level of accuracy compared with the target cost. The feasibility and the effectiveness of the proposed approach in value assessment, cost estimate, and optimization are demonstrated through a case study related to gas turbine blades. In the presented example, product value has been increased by lowering the manufacturing cost of key components while maintaining the same functions. Results highlight how the application of the proposed approach allows to reduce the overall cost of approximately 25% compared with the original design solution and to increase the product value up to 33%.