Dvitakčio variklio difuzoriaus skaitinė analizė

Abstract

Baigiamajame darbe yra analizuojamos dvitakčio variklio difuzoriaus srauto charakteristikos, gautos taikant skaitinį tyrimų metodą. Taikomas skaitinis metodas yra paremtas baigtinių tūrių metodu, kuriuo pasirinkta programinė įranga „Ansys“ apskaičiuoja pasirinktos geometrijos srauto charakteristikas pritaikant skirtingas ribines sąlygas. Skaitine programine įranga buvo sukurta variklio modelio, analogiško realiam varikliui, difuzoriaus ir alkūninio veleno sąveikos simuliacija. Tokiu būdu buvo ištirtos srauto charakteristikos, kurios vėliau buvo lyginamos su modifikuotos geometrijos difuzoriaus srauto charakteristikomis. Palyginus difuzoriaus skirtingų modifikacijų srauto charakteristikas buvo galima daryti išvadas, kokia geometrijos modifikacija perneša daugiausiai srauto į variklio vidų ir didina variklio efektyvumą. Darbą sudaro 5 dalys: įvadas, literatūros analizės ir tyrimo metodų apžvalga, dvitakčio variklio difuzoriaus tyrimas, išvados ir literatūros sąrašas. Darbo apimtis – 64 p. teksto be priedų, 41 iliustracija, 3 lentelės ir 31 literatūros šaltinis.

This master thesis, using numerical analysis method, examines airflow characteristics of specificic two-stroke engine. Mentioned analysis method in this thesis is based on finite volume method, which is applied by using specific software „Ansys“. By using mentioned software, characteristics of airflow are being analysed by applying different boundary conditions. Exact replica real two-stroke engine diffuser was recreated by using corresponding software. Recreated geometry was used to simulate working principle of this engine component, including its interaction with rotationary crankshaft. This way it was possible to analyze airflow characteristics of the whole process. Afterwards modifications were made to the geometry of the diffuser and same simulations were performed for each. All results and characteristics were compare between each other. After comparison conclusions were made and geometry modifications with best and worst performances were highlighted. Afterwards diffuser modification, which provided most airflow to the engine and had lowest ammound of pressure loss was concluded to be the most optimum for the work of whole two-stroke engine. Structure of thesis consists of 5 main parts: Introduction, literature analysis and overview of possible methods, two-stroke engine diffuser investigation, conclusions and references. Thesis consists of 64 p. of text without appendixes, 41 pictures, 3 tables and 31 references.