Konstruktionstudie av en ångexpander
This thesis applies to a novel steam expander, one part of a steam engine system, a wobble plateengine. The piston in the expander moves axially with the outgoing rotating shaft and is locatedon a plate, why the engine type is called axial engine. When steam is applied to the plungers theplate wobbles creating a rotation on the shaft going thru the wobble plate. The steam expander issupposed to be used in exhaust gas recovery (bottoming cycle) applications and small scaleenergy production. The commissioner is Ranotor Utveckling AB. The purpose with this thesis isto evaluate the design of the expander and if possible give advise on the reasonability of theconcept from a mechanical point of view. The pre study concerns the history of wobble plateengine as an internal combustion engine and steam expander, the engine?s principal layout andusage, applications today and other information that concerns the engine. A number ofcomponents are selected for further studies namely the piston and piston rod, the ball joint andthe wobble plate with bearings. The piston and piston rod is FE-modelled as a designoptimization. It is evaluated by measuring von Mises stress in different evaluation surfaces. Thestudy shows how the shape should be mass optimized and how this study can be valuable in thefuture. The ball joint is studied as a part that should be bought as a separate part and tested at therequired loads and environment. The component can?t be lubricated with oil (oil can have effectthe function of other components of the system negative) why lot of the attention is put onfinding a joint that works well without lubrication or with water in the contact. The wobble plateis studied by finding a kvasi-static operation point from a dynamic load modell of the steamexpander and applying these in static FE-modelled simulations. The wobble plate is equippedwith two bearings why an analytic study is made to find out how the position of the bearingschanges the load. The modell is verified by using a FE-modell and bearings are selected. The restof the study of the wobble plate is made on evaluating different kinds of supports for thebearings in a FE-modell and giving general advise concerning the solid mechanics of thecomponent and how the study should proceed.