PROFESSOR SARKOMAA'S MAIN FIELDS OF RESEARCH

During years 1970-1980, Professor Pertti Sarkomaa studied multiphase and multicomponent flows, and carried out in-depth research on the dimensioning of heat and fluid dynamics in nuclear reactors. The special focus was on operational safety.  He taught the theory of heat and fluid dynamics and safety in nuclear reactors from 1971 onwards.

    Professor Sarkomaa was a pioneer in experimental research on heat and fluid dynamics in nuclear reactors in Finland. He launched this research, funded by the Finnish Atomic Energy Committee, in his laboratory of Thermodynamics at LUT in years 1973-1975 in cooperation with the nuclear engineering laboratory at VTT Technical Research Centre of Finland.

    The first step was to build the initial test devices (REWET I …) including measurement systems, and to acquire technological knowledge, which is still today used in experimental research by the Laboratory of Nuclear Engineering at LUT.

    The laboratory has maintained its position as a nationally one-of-a-kind and a globally important research institute in the field of safety in light-water reactors. It has had a wide-ranging impact on the development of safety technology in Finnish nuclear engineering, and on safety in the Finnish nuclear power plants already in operation and ones being built. Professor Sarkomaa transferred 1980 the responsibility of nuclear energy safety research to professor of nuclear engineering doctor Heikki Kalli. The research is currently carried out in a research group of approximately ten researchers.

 

The Confederation of Finnish Industries and its member organizations, as well as the Finnish Forest Industries Federation together with SITRA, provided the funding for innovative energy research on energy conservation in years 1974-1976. The research developed many aspects of different technologies and aimed  at

- closing, improving and reforming the processes in order to reduce chemical losses, environmental loading and energy consumption, and to improving the overall economic situation of companies,

- substituting oil with other fuels, e.g. waste wood, bark and peat, and

- improving the quality of products and decreasing losses.

    The project developed a system of process simulation consisting of a number of innovations. The system was then employed as a tool in the project. Also a systematic energy certification method was developed in connection with the project. A scientific approach to thermodynamics, energy balances, and the second law of thermodynamics were systematically applied to the energy certification and reporting in the project. The project, headed by Professor Sarkomaa, was the most extensive of its kind in the field of energy research in Finland, and it was carried out as a collaborative effort of the most important industrial enterprises in their fields. The project achieved its goals, and the consumption of specific energy and oil was reduced considerably in Finnish industry. Professor Sarkomaa also coordinated a corresponding project related only to the forest industry. The project was funded by the Finnish Forest Industries Federation and SITRA in 1982-1983.

    In terms of the above and due to contacts with nearly all areas of energy-intensive industry in Finland, LUT Energy has for decades been a key partner in cooperation with industries with high energy consumption. LUT Energy has collaborated in reports related to rational industrial consumption of energy and in innovative research projects.

 

Professor Sarkomaa has developed a general method for physical and techno-economical optimization of the main parameters of product dimensioning (machines, equipment and processes). The method involves the definition of the investment in the product, the operating costs, and a target function for the product in accordance with the customer's investment criteria. The definitions are based on physics and technical dimensioning equations as a function of the main parameters, applying the specific prices of the prevailing market conditions. The optimized function and parameters are transformed into a dimensionless form. Thus the parameter values in the optimization problem in accordance with the Buckingham theorem are essentially reduced, and a general optimization solution can be defined.

    The laboratory has successfully applied the method in the optimization of different products for decades, for example heat exchangers for heat recovery, process heat exchangers and heat exchanger systems, district heating systems, process couplings of power plants, heat pumps, refrigerating machines, free cooling, etc.

    The general method developed in the project is very practical and opens up new possibilities in the area of product development. It allows dimensioning products individually to meet the customer's needs, taking the customer's values and investment criteria into consideration. The method yields products that are competitive from the perspective of the seller and suitable for specific customers. In some cases, wide-scale use of the method results in a considerable competitive edge, especially in one-off production and small batch sizes, which are typical in Finland.

 

    In years 1978-1981, an extensive study on the optimization of community energy systems was carried out in the LUT Laboratory of Thermodynamics. The research was headed by Professor Sarkomaa and funded by the Academy of Finland. The research results have mainly had an impact in the following three areas of application:

- The dimensioning regulations and guidelines of the Finnish District Heating Association were changed, and thus also the entire Finnish district heating system was affected.

- During the research, the laboratory headed by Professor Sarkomaa generated ideas and computer programs which were further developed into computer-aided HVAC dimensioning software. Advanced versions of this software are currently market leaders in Finland and Scandinavia.

- The research involved the development of simulation models for different types of district heating power plants. The simulation models have later been expanded and developed further into dimensioning and simulation software at LUT Energy and in companies operating in the field.

 

In 1981, Professor Sarkomaa launched research on high-speed technology, funded by the Ministry of Trade and Industry. The range of capacity and rotation speed dealt with in the study was novel both nationally and globally. The aim was first to develop a small-scale power plant which could convert the energy flow from hot industrial waste streams into electricity. The project manager was Jaakko Larjola, M.Sc. (Tech.). The industrial aspects of the project were very promising. First-generation high-speed technological solutions and the first model power plant were developed.

    Larjola continued to lead the project after he obtained his doctorate and was promoted to a permanent post as an professor in heat and fluid dynamics at LUT. High-speed technology was developed into its current form and commercialized by the research group. It contains e.g. gas and magnetic bearings, high-speed generators, high-speed motors, frequency transformers, radial high-speed turbines, high-speed pumps and high-speed compressors.

   The research group approximately ten people, are now working in the Laboratory of Electrical Engineering (LUT). The ground-breaking research in this field has had a significant effect on the development of related technology.

 

    One of the key research areas of the Laboratory of Thermodynamics Engineering - and of Professor Sarkomaa, who was in charge of the laboratory - has since its establishment in autumn 1972 been multiphase and multicomponent flows of reactants. The target of the research has been and still is improved, innovative modelling of phenomena based on experimental and theoretical research in order to support the research and development for products and processes. 

    The first doctoral dissertation in the area, completed in 1976, dealt with oxygen flame smelting. The doctoral candidate Seppo Ruottu worked later as a professor at LUT Energy. Important applications in this field include fluidization processes, e.g. circulated fluidized bed (CFB) combustion. The final dissertations supervised by Professor Sarkomaa in this research area dealt with the dynamics of magnetic fluids (Tero Tynjälä, D.Sc. (Tech.)), which is important in space and medical technology, and with medical technology itself (Mahsa Dabagh, D.Sc. (Tech.), and Arezou Jafari, D.Sc. (Tech.)).  

   Today, the research groups of LUT Energy employ several researchers who have obtained their doctorates from the Laboratory of Thermodynamics Engineering. They have published their research in world-leading, highly regarded scientific journals in this globally significant field of research.

 

Professor Sarkomaa has studied granular flows both experimentally and theoretically for approximately 35 years. Initially, the research focused on circulated fluid bed reactors, cyclones and solid material flows in pipes, and on nozzle research of fluidization. Since 1994, the research has involved theoretically very demanding analysis of basic phenomena, the results of which have been published in highly regarded, top scientific journals globally. Professor Sarkomaa has supervised a number of dissertations in this field.

 

Professor Sarkomaa has cooperated e.g. with the Defence Forces' Technical Research Centre in basic research related to their area of operation. The research has been financed by for instance the Scientific Advisory Board for Defence.