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1
Content available Application of the diagnostic plot in estimation of the skin friction in turbulent boundary layer under an adverse pressure gradient
Niegodajew P., Dróżdż A., Elsner W.
Archives of Mechanics
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2021
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Vol. 73, nr 2
201--215
EN
The paper concerns the problem of determining friction velocity in wallbounded flows affected by an adverse pressure gradient (APG). In the work of Niegodajew et al. [22] the corrected Clauser chart method (CCCM) for such flow conditions was proposed. This approach utilises the mean velocity profiles and turbulence intensity profiles to accurately estimate the friction velocity. In another work, Drózdz et al. [27] presented a modified version of the diagnostic-plot scaling (DPS) which allows for direct reconstruction of turbulence intensity profiles based on the local mean velocity profile, even when the flow is affected by a strong pressure gradient. This paper is aimed at verifying whether, when combining both of these methods (i.e. DPS and CCCM), the friction velocity can be accurately determined for APG flow conditions and one can possibly take advantage from both methods. The analysis revealed that the new approach is able to predict the friction velocity with uncertainty less than 5% for all the considered cases for the Clauser–Rotta parameter β < 17. Lastly, DPS-CCCM was also confronted with two empirical approaches (from available literature) allowing for estimation of the friction velocity under APG conditions. The performance of DPS-CCCM was found to be better than the ones of two other empirical approaches.
2
Content available remote Thermodynamic analysis and profitability study of a power unit with an added CO2 capture plant
Kowalczyk Ł., Niegodajew P., Drobniak S., Elsner W.
Journal of Power Technologies
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2016
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Vol. 96, nr 4
276--284
EN
Concerns over greenhouse gas emissions are driving a requirement for newly built coal power units to satisfy the so-called “capture ready” conditions. This paper presents the a thermo-economic analysis supplemented by a cost evaluation of a power unit for ultra-supercritical parameters expanded by an amine-based CO2 capture plant. The analysis was performed with the use of an integrated package containing the IPSEpro, MATLAB and Revenue Requirement Method implemented in MOExcel. The 0D model of a post combustion capture installation was developed based on complex CFD calculations of the absorber and stripper. A number of CFD simulations were conducted to create a large database, which was then utilized to develop suitable correlations describing the process Thermodynamic and economic calculations were performed in respect of a power plant coupled with a CO2 separation unit for a varying ratio of amine solvent to the exhaust gas stream (L/G). A local minimum for reboiler heat duty was found for L/G≈3.5 revealing the optimal post combustion capture configuration. It was observed that complementing the power unit with a post-combustion capture (PCC) installation causes a slight increase in the investment costs due to the drop in efficiency, but more important is the rise in total cost due to the investment associated with the CO2 capture plant. It was found that about 14 years is required to compensate the investment cost of the PCC installation.
3
Content available The Analysis of Nitrogen Oxides Formation During Oxygen - Enriched Combustion of Natural Gas
Poskart A., Radomiak H., Niegodajew P., Zajemska M., Musiał D.
Archives of Metallurgy and Materials
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2016
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Vol. 61, iss. 4
1925--1930
EN
This paper presents the study of oxygen–enriched combustion of natural gas and its impact on nitrogen oxides emission. The research were performed on two experimental stands, i.e. combustion chambers with an industrial swirl burner of maximum power equal to 90 kW and 10 kW. The investigation includes the influenced of oxygen enhanced within the range between 21% and 30%. Furthermore, the role of temperature during the oxygen enrichment was analysed. The results of the research showed that with the rise in oxygen concentration in the air the concentration of nitrogen oxides also increases what is directly related to the rise in flame temperature as well as the addition of oxygen.
4
Two–Phase Flow in Porous Bed with Chemical Reaction
Niegodajew P, Asendrych D., Drobniak S., Elsner W.
Zeszyty Naukowe. Mechanika / Politechnika Opolska
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2013
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z. 101
75--76
EN
Continuous growth of CO2 emission is one of the most important threats of today’s power industry. Among the alternatives allowing to solve that problem, carbon capture and storage (CCS) technology seems to be a very promising option. With this method the flue gases are being sent through the absorber where CO2 is captured by aqueous amine solution flowing countercurrently. Both phases pass through the packed bed where most of the chemical reaction occurs due to the enlarged contact area between phases. The research performed so-far included investigations with the use of laboratory or pilot installations as well as numerical modelling by means of simplified 0D or 1D models. These methods have, however, limited capabilities as they do not allow to have an insight into the details of the process.
5
Content available remote Numerical modelling of CO2 desorption process coupled with phase transformation and heat transfer in CCS installation
Niegodajew P., Asendrych D., Drobniak S.
Journal of Power Technologies
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2013
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Vol. 93, nr 5
354--361
EN
The paper concerns the research aimed at developing the computational fluid dynamics (CFD) model of amine based carbon dioxide capture process in post combustion capture (PCC) technology. Numerical model of absorber column (being the first stage of PCC cycle) including complex hydrodynamics, heat transfer and absorption reaction with the use of monoethanolamine (MEA) has already been developed and described in detail in [1, 2]. This paper focuses on the second stage of PCC cycle i.e. desorber (stripper) column. Eulerian multiphase model was adopted to resolve two-phase countercurrent gas-liquid flow in porous region with desorption reaction, multiphase heat transfer and evaporation/condensation phenomena. The preliminary calculations were performed on simplified geometry of stripper column in order to reduce the computational time required. Results have shown a physically correct behaviour, proving its relevance and its usefulness to practical applications.
6
Content available CFD modelling of CO2 capture in a packed bed by chemical absorption
Asendrych D., Niegodajew P., Drobniak S.
Chemical and Process Engineering
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2013
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Vol. 34, nr 2
269--282
EN
The paper deals with numerical modelling of carbon dioxide capture by amine solvent from flue gases in post-combustion technology. A complex flow system including a countercurrent two-phase flow in a porous region, chemical reaction and heat transfer is considered to resolve CO2 absorption. In order to approach the hydrodynamics of the process a two-fluid Eulerian model was applied. At the present stage of model development only the first part of the cycle, i.e. CO2 absorption was included. A series of parametric simulations has shown that carbon dioxide capture efficiency is mostly influenced by the ratio of liquid (aqueous amine solution) to gas (flue gases) mass fluxes. Good consistency of numerical results with experimental data acquired at a small-scale laboratory CO2 capture installation (at the Institute for Chemical Processing of Coal, Zabrze, Poland) has proved the reliability of the model.
7
Content available Numerical analysis of CO2 capture efficiency in post combustion CCS technology in terms of varying flow conditions
Niegodajew P., Asendrych D., Drobniak S.
Archives of Thermodynamics
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2013
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Vol. 34, no. 4
123--136
EN
The paper deals with the computational fluid dynamics modelling of carbon dioxide capture from flue gases in the post combustion-capture method, one of the available carbon capture and storage technologies. 30% aqueous monoethanolamine solution was used as a solvent in absorption process. The complex flow system including multiphase countercurrent streams with chemical reaction and heat transfer was considered to resolve the CO2 absorption. The simulation results have shown the realistic behaviour and good consistency with experimental data. The model was employed to analyse the influence of liquid to gas ratio on CO2 capture efficiency.
8
Modelowanie przeciwprądowego przepływu gaz - ciecz w złożu porowatym
Niegodajew P., Asendrych D.
Modelowanie Inżynierskie
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2012
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T. 14, nr 45
108--115
PL
Praca dotyczy modelowania przeciwprądowego przepływu dwufazowego gaz-ciecz w kolumnie z wypełnieniem porowatym. Wielofazowy model eulerowski został wykorzystany do opisania ruchu płynu w dwu-wymiarowej, osiowosymetrycznej domenie obliczeniowej. Jako czynniki zastosowane zostały woda i powietrze. Opory przepływu fazy dominującej, tj. gazu, zostały wyznaczone na drodze eksperymentalnej. Uzyskane wyniki obliczeń wskazują na adekwatność zastosowanego modelu do analizowanego przepływu.
EN
The paper deals with the numerical modelling of countercurrent flow through the absorber column with packed bed inside. Model geometry follows the real pilot plant absorber column localized in IChPW in Zabrze. The Euler-Euler model was applied to treat the gas-liquid system in 2-dimensional and axisymmetric domain. The flow is dominated by the gas phase and the liquid creates the film on the packed bed. The results obtained have shown the realistic behaviour of the system in terms of its hydrodynamics.
9
Content available remote Thermodynamic analysis of a thermal cycle of supercritical power plant
Elsner W., Kowalczyk Ł., Niegodajew P., Drobniak S.
Mechanics and Mechanical Engineering
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2011
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Vol. 15, nr 3
217-225
EN
The study presented in this paper deals with the analysis of operating conditions of a modern supercritical power plant. The 460 MW reference thermal cycle, which is based on the Łagisza supercritical, coal fired power plant was selected for this study. The thermodynamic analysis was performed with the use of the industrial software package IPSEpro, designed for power plant engineering. The main objective was to demonstrate the role of supercritical parameters in enhancing the efficiency of the thermodynamic process. It was done among the others by the comparative analysis of two thermal cycles, one working with standard and the other with supercritical parameters. Apart from nominal operating conditions part load operation was analyzed.
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