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A role of the heat and work uncompensated transformations in the balance of entropy and the turbomachinery eﬃcienc

Kowalczyk T., Ziółkowski P., Sławiński D., Cisak M., Badur J.

Transactions of the Institute of Fluid-Flow Machinery

2017

nr 135

11--27

The notion of heat uncompensated transformation has early been introduced by Clausius in 1854 and next, after ﬁfty years of forgetting, in 1904 Duhem has revalorized it and combined it with a new notion of work uncompensated transformation [3]. In this way the so-called ClausiusDuhem inequality has been established. In our paper we wish to present a novelized procedure of estimating the role of the uncompensated transformations of heat and work within the ﬂow of viscous and heat conducting working ﬂuid like water stream. The original procedure was introduced by Puzyrewski and it is essential in expressing of a local, in time and space, balance of entropy. Futhermore, this unique approach leads to redeﬁnition of the eﬃciency notion, as is usually applied to ﬂuid-ﬂow machineries, to a new one important in computational ﬂuid dynamics (CFD) three-dimensional modeling. As a result, it is shown that usage of the polytropic eﬃciency, instead of the isentropic eﬃciency, is more convenient and seems to be natural in CFD approach. Helpfully, we have also found a correlation between those two eﬃciency deﬁnitions with usage of proposed new dimensionless (criterion) number.

The methodology of the gas turbine efficiency calculation

Kotowicz J., Job M., Brzęczek M., Nawrat K., Mędrych J.

Archives of Thermodynamics

2016

Vol. 37, no. 4

19--35

In the paper a calculation methodology of isentropic efficiency of a compressor and turbine in a gas turbine installation on the basis of polytropic efficiency characteristics is presented. A gas turbine model is developed into software for power plant simulation. There are shown the calculation algorithms based on iterative model for isentropic efficiency of the compressor and for isentropic efficiency of the turbine based on the turbine inlet temperature. The isentropic efficiency characteristics of the compressor and the turbine are developed by means of the above mentioned algorithms. The gas turbine development for the high compressor ratios was the main driving force for this analysis. The obtained gas turbine electric efficiency characteristics show that an increase of pressure ratio above 50 is not justified due to the slight increase in the efficiency with a significant increase of turbine inlet combustor outlet and temperature.

Isentropic efficiency of a high-rotation speed refrigerating ejector

Kasperski J., Pietrowicz S.

Chemical and Process Engineering

2008

Vol. 29, z. 2

505-516

Concept of application of a rotation ejector in steam-driven, two-phase refrigeration cycle has been presented. The experimental results for a stationary ejector have been adapted to work conditions of a rotating ejector. For that purpose, a validated algorithm has been used as well as numerical simulation of thermal-flow processes based on the finite element method techniques. The effect of the entrainment ratio and rotational speed in the range from 0 to 10 000 rpm on induced pressure as well as on the isentropic and exergy coefficients have been analyzed.

Przedstawiono koncepcję zastosowania strumienicy obrotowej w parowym, dwufazowym obiegu chłodniczym. Wyniki badań doświadczalnych strumienicy nieruchomej zaadoptowano do warunków pracy strumienicy wirującej. W tym celu zastosowano sprawdzony algorytm badań oraz modelowanie numeryczne procesów cieplno-przepływowych oparte na metodzie elementów skończonych. Zanalizowano wpływ stopnia ejekcji i prędkości obrotowej strumienicy w zakresie 0.10 000 obr/min na ciśnienie ssania oraz współczynniki sprawności izentropowej i egzergetycznej.