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Classification of cardiovascular system according to the heart load

Nowak J., Marsik F.

Acta of Bioengineering and Biomechanics

2004

Vol. 6, nr 2

43-53

The aim of this paper was to show a possibility of determining energetic efficiency of the heart and to estimate the corresponding quality of the whole cardiovascular system of the man, with a simple non-invasive measurement only. For the examination we selected the probands whose cardiovascular systems demanded different energy. On the basis of clinical examinations we found the parameters A/i(/,, Kir They allowed us to measure the quality of the pumping ability and the efficiency of the cardiovascular system. These quantities made it possible to categorise the energy need of the heart and the compliance of the blood vessels.

Numerical analysis of cavitated flows in mixed-flow pump impellers

Sedlar M., Marsik F., Safarik P.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

2003

Z. 77

57-64

This paper deals with the flow model based on the Navier-Stokes computation and the simulation of bubble dynamics in the flow field, solving the Rayeigh-Plesset equation alongflow characteristics. No interaction between bubbles is considered. The initial bubble sizedistribution is based on a precribed distribution law and the initial void fraction. The flowpast the blades of mixed-flow pump impellers is investigated including the tip leakage flowsfor three different impeller configurations, aimed to predict the impeller configuration influence on cavitation phenomena, especially the blade surface regions endangered with the cavitation phenomena, especially the blade surface regions endangered with the cavitation erosion.

Condensation and cavitation in water and water mixtures

Marsik F., Delale C., Sedlar M.

Archives of Thermodynamics

2003

Vol. 24, no 1

3-16

The aim of this investigation is to reconsider the classical theory of homogeneous condensation and bubble nucleation by using real properties of fluids and non-equilibrium (dissipative) effects. To find out the influence of a chemical composition on the surface tension and consequently on the nucleation work and further to elucidate how the nucleation barrier is affected by the irreversible processes on the bubble surface the theoretical analysis is used. Both these effects are important for the nucleation and it is shown that they can increase (for condensation) the nucleation work. The theory is suitable both for pure substances and for their mixtures. The emphasis is laid on water condensation, boiling and cavitation.