ALGOR AROUND THE WORLD - Bulgaria
Algor Power Users Design Power Equipment

Sofia, Bulgaria is the home of two Algor power users, Kroum Georgiev, Ph.D., and Georgi Jadalov are mechanical engineers at Totema Ltd., a Sofia-based company which specializes in the development and assessment of power technology equipment. In addition to designing new components, the engineers utilize Algor software to estimate the remaining life of existing power equipment based on metal creep and cycle fatigue calculations.

Mechanical Engineers Kroum Georgiev, Ph.D., and Georgi Jadalov of Totema Ltd.

Many Analysis Types Used

"We used Algor software for steady-state and transient heat transfer as well as nonlinear stress analysis of turbine rotors, boiler drums, headers and steam pipelines," says Dr. Georgiev, "We also use Algor's PipePlus software to test and make adjustments to the supports and hangers for steam piping systems in thermal power plants."

Recently, the engineers took on two analysis challenges requiring the use of several Algor design and analysis packages. First, they were asked to determine the cause of deep cracks that were found in the casing of a valve box from a steam turbine after 70,000 hours of operation. "The analysis of nonlinear stress conditions in the valve box allowed us to determine that a problem in the design of the component had caused the cracking," says Mr. Jadalov. "We have now proposed a re-construction of the valve box based on our analysis. That work is proceeding."

Extending Component Life

Another analysis project called upon the engineers to assess the creep in the axial channel of a high pressure rotor from a steam turbine after 100,000 hours of operation. The purpose of the analysis was to estimate the remaining life expectancy of the shaft and propose a way to extend its service time.

Says Mr. Jadalov: "First, we used Timeload and the transient heat transfer processor to determine the transient temperature field in the shaft after a series of thermal shocks on the shaft surface. Then, Advance was used to translate the temperatures to the stress analysis model. Finally, the linear static stress processor was used to calculate the stress values."

Multiple Analyses Using the Same Model

"The ability of Algor software to perform thermal and stress analysis using the same model is very useful for the practical problems we have to solve," says Mr. Jadalov.