Marian Piwowarski

Design analysis of Tesla micro-turbine operating on a low-boiling medium

Design analysis of Tesla micro-turbine operating on a low-boiling medium This paper presents results of the design analysis of a Tesla bladeless turbine intended for a co-generating micro-power plant of heat capacity 20 kW, which operates in an organic Rankine cycle on a low-boiling medium. Numerical calculations of flow in several Tesla turbine models were performed for a range of design parameters. Results of investigations exhibit interesting features in the distribution of flow parameters within the turbine interdisk space. The calculated flow efficiency of the investigated Tesla turbine models show that the best obtained solutions can be competitive as compared with classical small bladed turbines.

Optimization of steam cycles with respect to supercritical parameters

Optimization of steam cycles with respect to supercritical parameters This paper contains an analysis of supercritical power stations have been presently built worldwide. The analysis concerns cycles with single and double interstage superheating and, additionally, with regenerative feed water preheating system equipped with six, seven, eight, nine and ten regenerative heat exchangers, respectively. Relevant calculations were performed for various values of fresh steam temperature and pressure, various pressure values of secondary superheating, as well as with value of condenser internal pressure maintained constant. The calculations show that to increase efficiency of steam cycle with double interstage superheating and extended regeneration even to a value greater than 51%, is possible. In the age of greater and greater demand for electric power and stronger and stronger limitations imposed on emission of noxious compounds to the atmosphere, the developing of power production technologies based on supercritical parameters seems inevitable.

Design analysis of turbines for co-generating micro-power plant working in accordance with organic Rankine's cycle

Design analysis of turbines for co-generating micro-power plant working in accordance with organic Rankines cycle This paper presents results of a design analysis of turbines for co-generating micro-power plant working in accordance with organic Rankines cycle and using biofuel. The heat power range from 25 kW to 100 kW with corresponding available electric power from 2kW to 12kW, was considered. Designs of axial-flow turbines (single-stage and multi-stage ones, also those partially fed), radial-flow and axial-radial -flow ones, were analyzed. Particular variants of the solutions were compared to each other.

Design and Investigations of a Micro-Turbine Flow Part

The co-generative micro-power plant with the HFE7100 as a working medium was designed and built for experimental investigations. The heat output of the plant was assumed equal to 20 kW, while the electric output amounted to about 3kW.In the paper a multi-stage micro-turbine with partial admission of all the stages is described in detail and the results of the particular experimental investigations and numerical calculations are shown, followed by an appropriate discussion and conclusions. The flow calculations were performed using ANSYS package and finally the axial multistage turbine was chosen. This allowed to apply typical nozzle and blade profiles. The turbine consists of 5 similar (almost identical) stages with constant section blades, the only difference being the increase of the admission arc (number of nozzles) in the successive stages. The rotor speed was assumed equal to 8000 rpm, mean rotor diameter −100 mm and blade height −10 mm. The stream lines, pressure and temperature distribution in the nominal and off-design conditions are presented and discussed in the paper. The micro-turbine was built and tested experimentally. The turbine performance was calculated for HFE7100 but also for air and nitrogen as a working medium for testing purposes. In the first stage of experiments the turbine behaviour was checked using these gases and the results were compared with the calculation data. The results of the experiments correspond very well with the appropriate CFD calculation data.Copyright

Design analysis of ORC micro-turbines making use of thermal energy of oceans

Abstract The article presents the results of the analysis of energy conversion cycles making use of thermal energy of oceans. The objects of analysis were two cases of closed Organic Rankine Cycle (ORC) power plants, which were: the cycle in which the vapour of the working medium was produced by warm oceanic water in the circum-equatorial zone, and the so-called “arctic” cycle in which this vapour was produced by non-frozen water in the circumpolar zone. Between ten and twenty low-boiling media were examined for which operating parameters were optimised to obtain the highest cycle efficiency. A preliminary design of an ORC turbine which was obtained by optimising basic design parameters is included. It has been proved that realisation of the Ocean Thermal Energy Conversion (OTEC) cycle is possible both in the warm and permanently frozen regions. The results of the calculations have also revealed that the efficiency of the OTEC cycle is higher in the circumpolar zone. Selecting a low-boiling medium and designing a highly efficient turbine operating in both abovementioned regimes is technically realisable.

Evaluation of technical efficiency of heat and electric power generation

Evaluation of technical efficiency of heat and electric power generation This paper presents an evaluation of technical efficiency and time-dependent changes in productivity of Polish professional electric power and heat & electric power stations by using Data Envelopment Analysis non-parametric method. The research covered the enterprises whose total available electric power amounted to about 98% of that of all professional thermal electric power stations in this country. The analysis has concerned the years 2000÷2004. Impact was considered of such factors as: scale of enterprise activity, form of ownership as well as type of carried out activity, on technical efficiency and time-dependent productivity changes. Changes in productivity of the power generation sector were determined by means of Malmquist index.

The Analysis of Turbine Propulsion Systems in Nuclear Submarines

The article systematises submarines, which are presently in service, according to their propulsion types (both conventional and nuclear), power output, and submersion depth. Contemporary types of propulsion systems installed and used in submarines are discussed. Calculations were performed for the PWR type nuclear propulsion system and the supercritical turbine propulsion system (supercritical reactor cooled with light water). Preliminary designs of turbines have been worked out for these two variants, and the systems were compared with respect to cycle efficiency and turboset efficiency.