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1
Content available remote Evaluation of bleed flow precooling influence on the efficiency of the E-MATIANT cycle
Rogalev A., Kindra V., Zonov A., Rogalev N., Agamirov L.
Mechanics and Mechanical Engineering
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2018
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Vol. 22, nr 2
593--602
EN
This study aims to present a method for precooling bleed flow by water injection in the E-MATIANT cycle and to estimate its impact on the overall efficiency. The design parameters of the cycle are set up on the basis of the component technologies of today’s state-of-the-art gas turbines with a turbine inlet temperature between 1100 and 1700◦C. Several schemes of the E-MATIANT cycle are considered: with one, two and three combustion chambers. The optimal pressure ratio ranges for the considered turbine inlet temperatures are identified and a comparison with existing evaluations is made. For the optimal initial parameters, cycle net efficiency varies from 42.0 to 49.8%. A significant influence of turbine stage cooling model on optimal thermodynamic parameters and cycle efficiency is established. The maximum cycle efficiency is 44.0% considering cooling losses. The performance penalty due to the oxygen production and carbon dioxide capture is 20-22%.
2
Content available Multi-parametric and multi-objective thermodynamic optimization of a spark-ignition range extender ICE
Toman R., Brankov I.
Journal of KONES
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2018
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Vol. 25, No. 3
459--466
EN
The current legislation pushes for the increasing level of vehicle powertrain electrification. A series hybrid electric vehicle powertrain with a small Range Extender (REx) unit – comprised of an internal combustion engine and an electric generator – has the technical potential to overcome the main limitations of a pure battery electric vehicle: driving range, heating, and air-conditioning demands. A typical REx ICE operates only in one or few steady-states operating points, leading to different initial priorities for its design. These design priorities, compared to the conventional ICE, are mainly NVH, package, weight, and overall concept functional simplicity – hence the costeffectiveness. The design approach of the OEMs is usually rather conservative: parting from an already-existing ICE or components and adapting it for the REx application. The fuel efficiency potential of a one-point operation of the REx ICE is therefore not fully exploited. This article presents a multi-parametric and multi-objective optimization study of a REx ICE. The studied ICE concept uses a well-known and proven technology with a favourable production and development costs: it is a two-cylinder, natural aspirated, port injected, four-stroke SI engine. The goal of our study is to find its thermodynamic optimum and fuel efficiency potential for different feasible brake power outputs. Our optimization tool-chain combines a parametric GT-Suite ICE simulation model and modeFRONTIER optimization software with various optimization strategies, such as genetic algorithms, gradient based methods or various hybrid methods. The optimization results show a great fuel efficiency improvement potential by applying this multi-parametric and multi-objective method, converging to interesting short-stroke designs with Miller valve timings.
3
Content available Performance optimization of organic Rankine cycles for waste heat recovery for a large diesel engine
Ma Z., Wu J., Zhang Y.
Archives of Thermodynamics
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2018
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Vol. 39, no 1
3--23
EN
In order to recover the low grade waste heat and increase system fuel economy for main engine 10S90ME-C9.2-TII(part load, exhaust gas bypass) installed on a 10000 TEU container ship, a non-cogeneration and single-pressure type of waste heat recovery system based on organic Rankine cycle is proposed. Organic compound candidates appropriate to the system are analyzed and selected. Thermodynamic model of the whole system and thermoeconomic optimization are performed. The saturated organic compound vapor mass flow rate, net electric power output, pinch point, thermal efficiency and exergy efficiency varied with different evaporating temperature are thermodynamically analyzed. The results of thermodynamic and thermoeconomic optimization indicate that the most appropriate organic compound candidate is R141b due to its highest exergy efficiency, biggest unit cost benefit and shortest payback time.
4
Content available Optimization of idealized ORC in domestic combined heat and power generation
Rybiński W., Mikielewicz J.
Archives of Thermodynamics
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2013
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Vol. 34, no. 3
137--146
EN
Organic Rankine cycle (ORC) is used, amongst the others, in geothermal facilities, in waste heat recovery or in domestic combined heat and power (CHP) generation. The paper presents optimization of an idealized ORC equivalent of the Carnot cycle with non-zero temperature difference in heat exchangers and with energy dissipation caused by the viscous fluid flow. In this analysis the amount of heat outgoing from the ORC is given. Such a case corresponds to the application of an ORC in domestic CHP. This assumption is different from the most of ORC models where the incoming amount of heat is given.
5
Content available Numerical thermodynamic optimization of supercritical coal fired power plant with support of IPSEpro software
Elsner W., Kowalczyk Ł., Marek M.
Archives of Thermodynamics
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2012
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Vol. 33, no. 3
101-110
EN
The paper presents a thermodynamic optimization of supercritical coal fired power plant. The aim of the study was to optimize part of the thermal cycle consisted of high-pressure turbine and two chosen high-pressure feed water heaters. Calculations were carried out using IPSEpro software combined with MATLAB, where thermal efficiency and gross power generation efficiency were chosen as objective functions. It was shown that the optimization with newly developed framework is sufficiently precise and its main advantage is the reduction of computation time on comparison to the classical method. The calculations have shown the tendency of the increase in efficiency, with the rise of a number of function variables.
6
Content available remote Contribution to the thermodynamics of the Co-Sn system
Vassilev G. P., Lilova K. I.
Archives of Metallurgy and Materials
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2006
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Vol. 51, iss. 3
365-375
EN
Comments on the available topological and thermochemical data of the Co-Sn system have been done. Updated data have been used in order to obtain adjustable coefficients for phase diagram calculation. In the present work both CoSn3 modifications are modelled as different phases. The binary melt and the Co-based phases with face centred cubic and hexagonal structures are modelled as substitutional solutions. The allotropic forms of tin (αSn, ΒSn) as well as the intermediate phases CoSn, CoSn2, αCoSn3 and ΒCoSn3 are modelled as stoichiometric compounds. The phases αCo2Sn3 and ΒCo2Sn3 are described by four sublattice model: (Co)1(Sn)1(Co,Va)0:5(Co,Va)0:5 in order to account for the order-disorder transition. Reasonable agreement has been obtained between the calculated and the selected experimental thermodynamic and phase equilibrium data.
PL
W artykule dokonano przeglądu dostępnych danych topologicznych i termochemicznych dla układu Co-Sn. Uaktualnione dane wykorzystano w celu uzyskania współczynników dopasowania potrzebnych do obliczeń wykresu fazowego. W pracy obie odmiany CoSn3 zostały zamodelowane jako różne fazy. Rozwtór ciekły, oraz fazy na osnowie Co o strukturze sześciennej ściennie centrowanej i heksagonalnej zamodelowano jako roztwory substytucyjne. Odmiany alotropowe cyny (αSn, ΒSn) a także fazy przejsciowe CoSn, CoSn2, αCoSn3, ΒCoSn3 potraktowano jako stechiometryczne związki. Wcelu uwzględnienia przemiany porządek- nieporządek fazy αCo2Sn3 i ΒCo2Sn3 zostały opisane modelem czterech podsieci: (Co)1(Sn)1(Co,Va)0:5(Co,Va)0:5. Wyselekcjonowane dane eksperymentalne oraz obliczone wykazywały zadawalającą zgodność.
7
Content available remote Problems of thermodynamics optimization
Szargut J.
Archives of Thermodynamics
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1998
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Vol. 19, no 3/4
85-94
EN
Four problems of thermodynamics optimization have been discussed: the maximization of the useful effect (finite time Thermodynamics), the minimization of the entropy generation, the optimization of the structure of thermal systems (pinch method) and the minimization of the depletion of unrestorable natural exergy resources. In each case the result does not equal the economic optimum. Advantages and disadvantages of the presented problems have been discussed.
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