Efficiency Optimisation of Blade Shape in Steam and ORC Turbines

Abstract

This paper is devoted to direct constrained optimisation of blading systems of large power and small power turbines so as to increase their internal efficiency. The optimisation is carried out using hybrid stochastic-deterministic methods such as a combination of a direct search method of Hooke-Jeeves and simulated annealing or a combination of a bat algorithm and simplex method of Nelder-Mead. Among free shape parameters are blade number and stagger angle, stacking blade line parameters and blade section (profile) parameters.One practical example of efficiency optimisation of turbine blading systems is modification of low load profiles PLK-R2 for high pressure (HP) stages of large power steam turbines. Another optimised geometry is that of an ORC radial-axial cogeneration turbine of 50 kWe. Up to 1% efficiency increase can easily be obtained from optimisation of HP blade profiles, especially by making the rotor blade more aft-loaded and reducing the intensity of endwall flows. Almost 2% efficiency rise was obtained for the optimised 50 kWe ORC turbine due to flow improvement at the suction side of the blade.

Compact High Efficiency and Zero-Emission Gas-Fired Power Plant with Oxy-Combustion and Carbon Capture

“…Velocity is high due to conditions at the last stage with extremely long blades (1.8 m). It is easier to achieve slower fluid velocity in smaller turbines; however, fluid velocity can reach 370 m/s even in small turbines, a value close to the speed of sound in conditions at the outlet of the turbine [140][141][142].…”

Additively Manufactured Parts Made of a Polymer Material Used for the Experimental Verification of a Component of a High-Speed Machine with an Optimised Geometry—Preliminary Research

“…In such cases, optimisations can be carried out simultaneously in several variants, taking into account economic aspects such as a cheaper and faster manufacturing process. An example of a very complex geometry is the rotor disc optimisation described in [ 37 , 47 ]. Geometry optimisation based on conventional methods can be very difficult, time-consuming and expensive (c) or even impossible (d).…”

“… Examples of geometry optimisations carried out on fluid-flow machines: ( a ) optimisation of the geometry of the blades of a gas microturbine [ 45 ]; ( b ) optimisation of the rotor of an air-breathing radial outflow turbine [ 46 ]; ( c ) optimisation of the guide vanes of an ORC microturbine [ 47 ]; ( d ) optimisation of the disc of a radial-axial turbine [ 37 ]. …”

“…So far, the optimisation of components such as the rotor discs of high-speed turbomachines has been experimentally verified only to the extent that enables the creation of such a geometry using the available manufacturing technologies. The rest of the optimised surfaces were either very difficult or very expensive to produce, for example, blades with less than 1 mm clearance or blades with a very complex profile [ 37 ]. Such obstacles prevented any experimental verification, leaving the optimisation outcome in the form of theoretical considerations.…”

The Performance of a Cross-flow Turbine as a Function of Flowrates and Guide Vane Angles

“…In contrast to the stream wheel, which is powered by the natural flow of water, an impulse turbine created at a high height is powered by a strong jet of water [1,2]. The ratio of static pressure drop in the rotor to static pressure drop in the stator or nozzle plus the rotor [3,4] is the degree of response, which is defined as the differential in the pressure drop between the nozzle and the rotor. Impulse turbines work by a high-velocity jet exerting force on the rotor blades, with the nozzle converting all of the potential energy into kinetic energy before the flow passes through the blades.…”