Development of a Water Brake Dynamometer With Regard to the Modular Product Design Methodology

This paper summarizes a research project in the field of design and manufacturing of a water brake dynamometer for power testing facilities. In the current study, the design process of a water brake with drilled rotor disks is presented. This process is examined against the development of a water brake for a 4MW gas turbine power measurement at 15,000 RPM speed. The proposed algorithm is based on vital assumptions such as; applying product designing issues and limited modular analysis that urges the disciplinary attitude and leads to the possibility of rapid development, easy maintenance and ease of access. The final scheme is divided into six disciplines with functional classification. These disciplines are rotor, housing, cabs, pedestals, skid and accessories. Accessories, itself, consist of cooling system, lubricating system and control unit. Every discipline has its special function and could be optimized separately. It is possible to change any discipline specification without affecting other disciplines modularity. Using FEM software makes it easy to analyze the mechanical component for static and dynamic load condition regarding complex initial and boundary condition. But it is not wise to analyze whole system for designing a product due to numerical calculation errors. Besides, it is not necessary to use calculation to select machine elements. Rotor dynamics is investigated with modal analysis and related Campbell diagram. Also, transient analysis on housing, rotor and load cell arm is presented. The modal analysis on pedestals and skid is performed to predict the structural behavior under periodic loads caused by rotating unbalance. The process presented in this paper is a method for design of water brake dynamometer. Modularity presented by a product tree and a trend for design cycles associated with computer simulation are the basis of this method. The final product that is designed with this algorithm is successfully manufactured and tested.