This thesis deals with large-scale cylindrical interface sealing between the hot gas path components of silo combustion chamber. Implementation of hula seal for replacing old belt seal will be checked in order to minimize the amount of cooling and leakage air, without negative impact on the lifetime of the components. Hula seal is annular flexible spring finger seal used to compensate misalignment between co-annular parts, while providing effective sealing performance. It is circumferential metal seal that is slotted in the axial direction and contoured to be spring-loaded between inner and outer diameter of the matching parts that experience relative axial motion. Long term successful implementation of the hula seal for sealing of stationary interfaces for industrial and aero gas turbine engines confirms benefits like improved lifetime of the hot gas parts, reduction of manufacture costs and on-site assembly time. The target engine type is older gas turbine that currently uses belt seal as seal for cylindrical interface between the hot gas path components of silo combustion chamber. Main reason of choosing this engine is the highest wear impact and costs of the belt seal compared to other engines. In scope of this thesis computational fluid dynamics method is used to verify the sealing performance of the hula seal and compare it with belt seal performance. Models of belt seal, combustion inner liner and hot gas casing that are used already existed, while hula seal model was designed by descriptions from patent. From this models, assembly of two cases were made, one for belt seal case and one for hula seal case. Periodic models were created from assembly models to reduce mesh generation and computational time. Numerical analysis solved conjugate heat transfer problem which means that along fluid flow, heat transfer interaction between fluid and solid was solved as well. Result which shows fluid flow and thermal condition of fluid and solid are presented. Based on result it is concluded that performance of hula seal model used in this thesis are not good enough. Compared to belt seal hula seal cooling performances are worse. Suggestions for improving hula seal performance were given.