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1
Content available remote Elements of supercritical CO2 cycle - mathematical modeling and validation on available experimental data
Milewski Jarosław, Szczęśniak Arkadiusz, Szablowski Łukasz, Futyma Kamil, Lis Piotr, Dybiński Olaf, Wołowicz Marcin
Journal of Power Technologies
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2022
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Vol. 102, nr 1
1--13
EN
This paper presents models of three elements: heat exchanger, compressor and expander dedicated to supercritical CO2 cycles (Brayton). The models are built using Ebsilon software and validated against experimental data from available literature. Radial turbomachinery and thin plate heat exchangers were used to meet the demands of the relatively compact design of the S-CO2 cycle elements. It seems that there are no general relationships for the turbomachinery and real characteristics need to be used for constructing the models.
2
Content available remote Selected issues of the structures and parameters of supercritical CO2 gas turbine cycles
Milewski J., Futyma K., Szcześniak A., Wołowicz M., Ziembicki G.
Mechanics and Mechanical Engineering
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2018
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Vol. 22, nr 2
565--583
EN
The paper presents a variant analysis of the structures of closed gas turbines using supercritical carbon dioxide (super-CO2) as a working fluid. Several configurations covered in the available literature were collected, commented on and compared. The parameters of the cycles, such as operating temperature and heat supply are noted and commented on. There are three main configurations considered in the available literature: the precompression cycle, partial cooling cycle, and recompression cycle.
3
Content available Comparative analysis of effeciency of waste heat conversion in low-temperature Brayton cycle
Borsukiewicz A., Stawicki P.
Chemical and Process Engineering
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2018
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Vol. 39, nr 1
103–-112
EN
The paper discusses the feasibility, effectiveness and validity of a gas turbine power plant, operated according to the Brayton comparative cycle in order to develop low-potential waste heat (160◦C) and convert it into electricity. Fourteen working fluids, mainly with organic origin have been examined. It can be concluded that low molecular weight working fluids allow to obtain higher power efficiency of Brayton cycle only if conversions without taking into account internal losses are considered. For the cycle that takes into account the compression conversion efficiency in the compressor and expansion in the gas turbine, the highest efficiency was obtained for the perfluoropentane working medium and other substances with relatively high molecular weight values. However, even for the cycle using internal heat recovery, the thermal efficiency of the Brayton cycle did not exceed 7%.
4
Content available Energy analysis of municipal waste in Dubrovnik
Król P., Krajačić G.
Acta Innovations
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2018
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no. 28
40--48
EN
In each touristic city waste management system has to overcome the impact of visitors. Dubrovnik, famous as popular touristic destination, particularly notices tourists visiting city. Therefore potential impact of waste management in touristic cities, such as Dubrovnik, is presented. The paper includes estimation of yearly waste production by inhabitants and tourists visiting those city. Waste digestion is a method for biogas production. On the basis of the preceding estimation combined-cycle installation generating heat and electricity is proposed. The model combines Brayton cycle with low temperature Kalina model based on Rankine cycle. Literature analysis presents state of the art in this field. The simulation is prepared in Cycle-Tempo. Numerical analyses lead to technical issues, which have to be taken into consideration during waste utilization with such installation. Thus benefits and threats are discussed. The presented analysis assesses the maximal electric gain, which subsequently should consider waste preparation and purification.
5
Content available remote Method of modeling gas turbine performance
Wasik P., Krzyślak P.
Journal of Mechanical and Transport Engineering
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2017
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Vol. 69, No. 1
61--79
EN
The basis of a combined cycle gas turbine mass and energy balance, carried at the concept stage, preliminary design or during analysis, is the calculation of the gas turbine design point. This article presents a gas turbine unit mathematical modelling process intended for implementation of the model in a computer program. The aim of the development was a relatively simple, practical from engineer’s point of view, and universal gas turbine model with a classic, open system design: compressor – combustion chamber – turbine. Attempts have been made to maintain the accuracy of modelling and to keep the ability for extension of the model so to be able to simulate the operation of the turbine at off-design conditions, in particular at part load. Stationary operation of the unit at nominal load is assumed. Thermodynamic system modelling methods, on the level of its global structure, have been submitted. Problems related to the aforementioned issues are discussed and ways to resolve them proposed. The developed model has been implemented in a dynamic link library written in C++ language with usage of C/C++ Minpack numerical library [Keating 2007, Razak 2007].
PL
Zwiększający się w światowym bilansie produkcji energii elektrycznej udział energii wytwarzanej z gazu ziemnego warunkuje tempo przyrostu ilości elektrowni i elektrociepłowni gazowo parowych. Pomimo wysokich cen gazu ziemnego, bloki gazowo parowe są atrakcyjne dla inwestorów z uwagi na: najwyższą sprawność wśród stosowanych na szeroką skalę instalacji energetycznych zasilanych paliwami kopalnymi, dopracowaną technologię skutkującą wysoką niezawodnością, wysoką elastyczność eksploatacyjną, słabe oddziaływanie na środowisko (niskie emisje dzięki wysokiej sprawności i opalaniu gazem ziemnym). Podstawą obliczeń układu kombinowanego na etapie koncepcjonowania/projektowania wstępnego lub podczas jego analizowania są obliczenia turbozespołu gazowego pracującego w punkcie konstrukcyjnym. W artykule przedstawiono krok po kroku proces modelowania matematycznego zespołu turbiny gazowej pod kątem implementacji modelu w programie obliczeniowym. Założono stacjonarną pracę układu przy pełnym obciążeniu. Przewidywanym zastosowaniem modelu jest przede wszystkim symulacja turbiny gazowej skojarzonej z parowym kotłem odzyskowym, tym samym działającej w kombibloku. Omówiono problemy związane z poruszanym zagadnieniem oraz zaproponowano sposoby ich rozwiązania.
6
Content available Dual ORC-Brayton power system for waste heat recovery in heavy-duty vehicles
Cholewiński M., Pospolita W., Błoński D.
Archives of Transport
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2016
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Vol. 39, iss. 3
7--19
EN
Reducing the amount of energy required in industrial activities is one of the proven ways to achieve major cost savings, especially in the face of soaring energy prices. In the transport sector, besides the financial benefits, low energy consumption leads to the significant reduction of emissions of many pollutants. In this paper the new concept of dual power technology, dedicated to heavy road transport, was modelled and analysed by computer simulations. The combination of organic Rankine cycle and Brayton cycle was proposed, where the waste heat of fumes was recognized as a upper heat source, whereas the surrounding was adopted to be the lower one. Improvement of total energy conversion efficiency of the truck was the key success factor. Environmental friendly fluids (air and R123) were utilised. The operating parameters, power characteristics and energy streams (i.e. dispersion) of the system were evaluated, calculated and commented from the perspective of its theoretical profitability. The calculated net power capacity of analysed dual system was around 50 hp for 100% load. However, when the engine load is below 50% of nominal capacity, the power generation of combined system might be lower than in the case of single ORC system.
7
Content available remote Model of an ANSALDO V94.2 gas turbine from Lublin Wrotków Combined Heat and Power Plant using GateCycle™ software
Kowalczyk B., Kowalczyk C., Badyda K., Rolf R. M.
Journal of Power Technologies
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2014
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Vol. 94, nr 3
190--195
EN
This paper concerns the model of the ANSALDO V94.2 gas turbine for variable operating conditions from CHP Lublin Wrotków. General Electric GateCycle™ software was used to build the model. The gas turbine modeling methods used in the software were described. To assess the model, computations were performed for 40% and 70% load for 0.9, 14 and 30 ºC ambient temperature and 100% load for -20, 0.9, 14, 15 and 30 ºC ambient temperature. The results were compared with available heat balances of the object. The paper also discusses the theory of gas turbines, considering the sensitivity of the thermodynamic cycle.
8
Content available Thermodynamic analysis of the double Brayton cycle with the use of oxy combustion and capture of CO2
Ziółkowski P., Zakrzewski W., Badur J., Kaczmarczyk O.
Archives of Thermodynamics
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2013
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Vol. 34, no. 2
23--38
EN
In this paper, thermodynamic analysis of a proposed innovative double Brayton cycle with the use of oxy combustion and capture of CO2, is presented. For that purpose, the computation flow mechanics (CFM) approach has been developed. The double Brayton cycle (DBC) consists of primary Brayton and secondary inverse Brayton cycle. Inversion means that the role of the compressor and the gas turbine is changed and firstly we have expansion before compression. Additionally, the workingfluid in the DBC with the use of oxy combustion and CO2 capture contains a great amount of H2O and CO2, and the condensation process of steam (H2O) overlaps in negative pressure conditions. The analysis has been done for variants values of the compression ratio, which determines the lowest pressure in the double Brayton cycle.
9
Content available Enhancement of the Brayton cycle efficiency by water or steam utilization
Jesionek K., Chrzczonowski A., Ziółkowski P., Badur J.
Transactions of the Institute of Fluid-Flow Machinery
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2012
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nr 124
93--109
EN
In the paper, thermodynamic analysis of two modifications of the Brayton cycle into enhancement cycles with water or steam injection are discussed. The first one deals with a water injected gas turbine modified system with both interstage compressed air cooling and air heating (heat regeneration) before combustion chamber. The second one, mainly devoted to higher steam to air ratio, is connected with separate steam production in the heat recovery steam generator. Hence, steam utilization for the gas turbine propulsion in the Cheng cycle has been analysed. The analysis has been based on the computational flow mechanics (CFM) models of these advanced humidified systems, thanks to which, the influence of the main thermodynamic and design parameters have been examined.
10
Content available remote Performance analysis of a gas turbine air heat recovery unit using GateCycle® software
Kowalski M., Badyda K.
Journal of Power Technologies
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2012
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Vol. 92, nr 1
48-54
EN
The following article concerns the results of an analysis of a gas turbine (GT) with an air heat recovery turbine unit (AHRTU) using General Electric GateCycle® software. The analysis was conducted for five different variants of air heat recovery turbine units: (i) simple AHRTU, (ii) with air cooling by one intercooler, (iii) with air cooling by two intercoolers, (iv) with variable humidity before the compressor, and (v) with water injection into the compressor. Each variant was tested for four different air temperatures before air turbine (ATBAT): 573 K, 673 K, 773 K, and 873 K. For each air temperature before air turbine, computations were run for increasing compression ratios (CR): from 3 to 6.5 for variants 1 and 4 and from 3 to 12 for variants 2,3 and 5. The results were shown as graphs of specific power (SP) of the AHRTU versus compression ratio in the AHRTU.
11
Content available Power enhancement of the Brayton cycle by steam utilization
Jesionek K., Chrzęszczyk A., Ziółkowski P., Badur J.
Archives of Thermodynamics
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2012
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Vol. 33, no. 3
39-50
EN
The paper presents thermodynamic analysis of the gas-steam unit of the 65 MWe combined heat and power station. Numerical analyses of the station was performed for the nominal operation conditions determining the Brayton and combined cycle. Furthermore, steam utilization for the gas turbine propulsion in the Cheng cycle was analysed. In the considered modernization, steam generated in the heat recovery steam generator unit is directed into the gas turbine combustion chamber, resulting in the Brayton cycle power increase. Computational flow mechanics codes were used in the analysis of the thermodynamic and operational parameters of the unit.
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