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1
Stationary shock-wave in the flow of a water-vapour mixture
100%
Kwidziński R.
Zeszyty Naukowe Instytutu Maszyn Przepływowych Polskiej Akademii Nauk w Gdańsku
|
1999
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tom nr 498/1458
1--119
2
Wpływ geometrii strumienicy dwufazowej parowo-wodnej na charakterystyki jej pracy
63%
Trela M. , Kwidziński R.
Inżynieria i Aparatura Chemiczna
|
2006
|
tom Nr 6s
239-241
EN
The paper presents experimental results and theoretical investigations of supercritical two-phase flow in a steam - water injector. Experiments included measurements of the maximum exit pressure for a varying cross-section of the mixing chamber throat. The pressure mentioned and flow losses were estimated theoretically using the global momentum balance in a mixing chamber.
3
Content available remote Modelling of physical phenomena in supercritical two-phase steam injector
63%
Trela M. , Kwidziński R.
Archives of Thermodynamics
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2003
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tom Vol. 24, no 4
15-34
EN
The paper considers problems specific to physical description and modelling of two-phase flow in supercritical steam injector. Flow patterns, condensation and a shock wave are discussed. The model of annular flow for the mixing chamber is proposed and used to determine scaling criteria. Thereafter average heat exchange coefficient in the mixing chamber is evaluated from correlation of experimental data. A model based on the concept of macroscopic viscosity, describing the wave is also presented.
4
Content available remote Control stage flow. Part I. Turbine nominal load
51%
Lampart P. , Szymaniak M. , Kwidziński R.
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tom nr 133
201--206
EN
The partial admission control stage of a 200 MW steam turbine is studied using CFD and a 3D full-geometry model. The first part of the paper is devoted to the operation of the turbine at nominal load conditions when three (out of four) control valves are fully open, the forth valve is partly open. The circumferential non-uniformity of flow patterns and rotor blade forces are calculated and discussed.
5
Content available remote Exergy analysis of losses in a two-phase steam-water injector
51%
Trela M. , Kwidziński R. , Butrymowicz D.
Chemical and Process Engineering
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2008
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tom Vol. 29, z. 2
453-464
EN
Exergy losses in elements of a steam-water injector have been determined. Exemplary calculations based on the experimental data showed that the highest irreversible losses take place in a two-phase flow in the mixing chamber and in the shock wave region. The exergy efficiency for the injector, defined as the outlet to inlet exergy ratio, has been found to lie in the range of 28-36%.
PL
Wyznaczono straty egzergii w elementach składowych strumienicy parowo-wodnej. Na podstawie obliczeń opartych na wynikach badań eksperymentalnych stwierdzono, że największe straty nieodwracalności występują w przepływie dwufazowym w komorze mieszania i w obszarze fali uderzeniowej. Obliczono także sprawność egzegetyczną, zdefiniowaną jako iloraz egzergii wylotowej i wlotowej, która dla badanej strumienicy wynosiła 28-36%.
6
Content available Analysis of application of feed-water injector heaters to steam power plants
51%
Trela M. , Kwidziński R. , Głuch J. , Butrymowicz D.
Polish Maritime Research
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2009
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tom S 1
64-70
EN
Steam-water injectors are devices in which exchange of mass, momentum and energy between two fluids being in direct contact, occurs. They can operate as pumps, mixers or direct contact heat exchangers. In the last aspect their use as feed-water heaters in Rankine thermal cycle of steam power plants both in land and sea applications (to merchant and naval ships) is very interesting. This paper presents selected results of heat-and-flow investigations of a supercritical steam-water injector, obtained in Institute of Fluid Flow Machinery, Polish Academy of Sciences (IMP PAN). On their basis value of average heat transfer coefficient for mixing chamber was determined; the obtained values were even a few dozens greater than those for classical shell-and-tube heaters. In the theoretical part of this work is presented an original injector model based on balances of mass, momentum and energy, written for control volumes containing separately particular elements of injector. On the basis of the model flow parameters in characteristic cross-sections of injector were determined. The calulations were performed for two different injectors tested in IMP PAN (Gdańsk) and SIET (Piacenza, Italy), and their good compliance with experimental data was achieved.
7
Content available Experimental observations of flow structures during DEP controlled boiling in a microchannel
51%
Lackowski M. , Kwidziński R. , Karwacki J. , Przybyliński T.
Archives of Thermodynamics
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2018
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tom Vol. 39, no 1
129--145
EN
The paper presents results of experimental investigation of microchannel boiling flow which was controlled by dielectrophoretic (DEP) restrictor. The DEP restrictor was connected to the microchannel liquid supply tube. Operation of DEP restrictor influenced the flow rate at the microchannel inlet. Resulting changes in flow structures and vapour content along the microchannel were observed and analysed with a high-speed video camera. Video recordings were synchronised with measurements of differential pressure between the channel inlet and outlet. It was found that it is possible to change average void fraction in the microchannel by switching on and off the voltage applied to the restrictor electrodes. However, to achieve significant variation of the void fraction, applied voltage should be of the order of 2000 Vpp. The voltage switching also generates oscillations of the differential pressure. The amplitude of these oscillations is proportional to the voltage magnitude, reaching 35 Pa for 2400 Vpp.
8
Content available A defnition of near-critical region based on heat capacity variation in transcritical heat exchangers
51%
Trela M. , Kwidziński R. , Butrymowicz D.
Archives of Thermodynamics
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2011
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tom Vol. 32, no. 2
55-68
EN
In the paper, a method for determination of the near-critical region boundary is proposed. The boundary is evaluated with respect to variations of specific heat capacity along isobars. It is assumed that the value of specific heat capacity inside the near-critical region exceeds by more than 50% the practically constant value typical for fluids under normal conditions. It appears that large variations of heat capacity are also present for high-pressure subcritical states sufficiently close to the critical point. Therefore, such defined near-critical region is located not only in supercritical fluid domain but also extends into subcritical fluid. As an example, the boundaries of the near-critical region were evaluated for water, carbon dioxide and R143a.
9
Content available remote Maximum discharge pressure of supercritical two-phase steam injector
51%
Trela M. , Kwidziński R. , Buła M.
Archives of Thermodynamics
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2004
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tom Vol. 25, no. 1
41-52
EN
The paper aims at the determination of the maximum output pressure as one of the pertinent parameters describing the steam injector performance. Experimental and theoretical results of discharge pressure investigation from steam-water injector are presented. Experiments included measurements of output pressure dependence on varying inlet flow rates of both media and on the water nozzle gap. Maximum output pressure obtained reached 97% of the inlet vapour pressure. Performance of the steam injector is described mathematically using momentum balance in mixing chamber and shock wave region. Loss coefficient of the steam injector is also determined. Having the loss coefficient one can evaluate the maximum pressure for geometry similiar steam injectors. From the analysis of the balance equations, the ways of increasing the maximum discharge pressure are suggested.
10
Content available remote The speed of sound in the homogeneous vapour-liquid mixture
51%
Downar-Zapolski P. , Bilicki Z. , Kwidziński R.
Archives of Thermodynamics
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1998
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tom Vol. 19, no 1/2
5-31
EN
This paper investigates the influence of non-equilibrium phase transition in the vapour-liquid mixture on the properties of sound waves. A dispersion relation for small disturbances has been found and analysed. The investigation of evolution of a linear wave in the vapour-liquid mixture creates the background for conclusions concerning a speed of sound in dispersive media.
11
Badania eksperymentalne pracy dwufazowej pompy strumienicowej pracującej z izobutanem
45%
Przybyliński T. , Butrymowicz D. , Karwacki J. , Śmierciew K. , Kwidziński R.
Chłodnictwo : organ Naczelnej Organizacji Technicznej
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2014
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tom R. 49, nr 1
6--10
PL
W artykule przedstawiono wyniki badań eksperymentalnych pracy dwufazowej pompy strumienicowej w zastosowaniu do układów chłodniczych. Badania przeprowadzono dla strumienicy pracującej z izobutanem. W artykule przedstawiono opis stanowiska badawczego oraz wyniki eksperymentów w postaci charakterystyk pracy strumienicy oraz współczynnika wnikania ciepła.
EN
Paper deals with experimental investigation of two-phase vapour-liquid injector as a liquid pump in refrigeration systems. The experiment results for the injector are presented for the case of isobutane as working fluid. Experimental data was shown as the operation characteristics of the injector as well as heat transfer coefficient.
12
Content available remote Badanie strat przepływowych w wieńcach łopatkowych stopni turbinowych z wykorzystaniem CFD. Cz. II Charakterystyki sprawnościowe
45%
Gardzilewicz A. , Lampart P. , Świrydczuk J. , Kwidziński R. , Kosowski K.
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
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2000
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tom nr 117, vol. 1
187-192
PL
W Części II pracy nt. numerycznych badań strat przepływowych w wieńcach stopni turbinowych zamieszczono przykładowe charakterystyki palisad kierowniczych i wirnikowych części WP dla różnych parametrów geometrycznych i przepływowych palisady, opracowane przy użyciu metodologii przedstawionej w Części I. Charakterystyki te obrazują wpływ głównych parametrów geometrycznych, takich jak smukłość łopatki, podziałka palisady, kąt ustawienia profilu, oraz przepływowych, jak liczba Macha i kąt napływu strumienia, na współczynnik strat energii kinetycznej.
EN
Part II of the paper on CFD investigations of flow losses in turbine cascades presents sample characteristics of HP stator and rotor performance in a range of geometrical and flow parameters. The characteristics are elaborated based on the methodology described in Part I and illustrate the impact of the main geometrical parameters, like the chord/span ratio, pitch/chord ratio and stagger angle as well as flow parameters like the Mach number or inlet angle on the coefficient of kinetic energy losses.
13
Content available remote Badanie strat przepływowych w wieńcach łopatkowych stopni turbinowych z wykorzystaniem CFD. Cz. I Metoda obliczeniowa
45%
Gardzilewicz A. , Świrydczuk J. , Lampart P. , Kwidziński R. , Kosowski K.
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
|
2000
|
tom nr 117, vol. 1
179-186
PL
Czasochłonna i kosztowna eksperymentalna procedura określenia charakterystyk palisad łopatkowych maszyn wirnikowych potrzebna dla projektowania turbin w modelach ID coraz częściej bywa zastępowana badaniami numerycznymi techniką CFD. W pracy omówiono badania przepływu w wieńcach kierowniczych i wirnikowych stopni turbinowych z krótkimi łopatkami cylindrycznymi w celu określenia ich charakterystyk sprawnościowych. W części I przedstawiono metodę wyznaczania charakterystyk przy użyciu programu 3D do obliczeń stopni turbinowych. Podano przykładowe rezultaty badań ilustrujące rozwój pola prędkości w kluczowych przekrojach, narastanie entropii w kanale przepływowym, rozkład strat i przebieg zmian kąta wylotowego wzdłuż wysokości kanału dla różnych wysokości względnych łopatek.
EN
More and more often, the time-exhaustive and cost-ineffective experimental procedure for the determination of characteristics of turbomachinery cascades necessary for ID-based design is replaced by numerical investigations with the aid of CFD. The paper reports on flow investigations in stator and rotor cascades of short-height turbine blading aiming at the determination of their efficiency characteristics. Part I is meant to describe the applied method of calculation using a 3D code. Sample results of investigations are also enclosed to illustrate the development of velocity fields in crucial sections, streamwise increase of the entropy, as well as spanwise distribution of losses and exit angle for a changing span-to-chord aspect ratio.
14
Content available New results from microalgae production and techniques
38%
Grossmann J. , Matthes S. , Karwacki J. , Kwidziński R. , Tomaszewski A. , Lackowski M. , Cenian A.
Eco-Energetics : technologies, environment, law and economy
|
2019
|
tom T. 2
47--62
EN
The paper deals with new technical solutions for outdoor cultivation systems for microalgae production. Various types of algae cultivation systems and materials applied for reactors are described. The characteristics and performance of a novel closed photobioreactor system with “Christmas tree” design (brand name: GICON-PBR) consisting of a silicone double-wall tubing-system, developed in collaboration between the companies GICON and Wacker Chemical corporation, are discussed. Special attention is paid to the issue of temperature control for closed cultivation systems. The performance of the chilling system stabilizing the temperature of algae cultivation, which applies a thermal energy storage filled with Phase Change Material (PCM). Two kinds of the systems are considered: free cooling and with compressor units. The lumped-model equations were developed to analyze heat-transfer dynamics inside the installation and some results are presented here. The model equations describe energy balances for the chiller, PCM thermal storage and heat receiver. Influence of the heat transfer, fluid-flow-rate control, heat capacity of the system components as well as heat losses to ambient were taken into account. The results of PCM storage application are compared with reference water-filled buffer-tank. The study shows a great potential of PCM storage unit to stabilize the temperature of the algae cultivation system.
15
Content available Methodology of heat transfer and flow resistance measurement for matrices of rotating regenerative heat exchangers
32%
Butrymowicz D. , Karwacki J. , Kwidziński R. , Śmierciew K. , Gagan J. , Przybyliński T. , Skiepko T. , Łapin M.
Chemical and Process Engineering
|
2016
|
tom Vol. 37, nr 3
341--358
EN
The theoretical basis for the indirect measurement approach of mean heat transfer coefficient for the packed bed based on the modified single blow technique was presented and discussed in the paper. The methodology of this measurement approach dedicated to the matrix of the rotating regenerative gas heater was discussed in detail. The testing stand consisted of a dedicated experimental tunnel with auxiliary equipment and a measurement system are presented. Selected experimental results are presented and discussed for selected types of matrices of regenerative air preheaters for the wide range of Reynolds number of gas. The agreement between the theoretically predicted and measured temperature profiles was demonstrated. The exemplary dimensionless relationships between Colburn heat transfer factor, Darcy flow resistance factor and Reynolds number were presented for the investigated matrices of the regenerative gas heater.
16
Content available remote Zagadnienia oceny efektywności energetycznej prototypowego układu chłodniczego obsługującego chłodnię składową warzyw
32%
Butrymowicz D. , Gagan J. , Śmierciew K. , Dudar A. , Łukaszuk M. , Mizera G. , Karwacki J. , Kwidziński R. , Przybyliński T.
Instal
|
2018
|
tom nr 6
23--28
PL
Zastosowanie pośredniego systemu chłodzenia w układach chłodniczych obsługujących komory składowe warzyw bądź owoców można uznać za perspektywiczne rozwiązanie. Umożliwia on uzyskanie stabilnej temperatury towaru zbliżonej do temperatury krioskopowej, stabilną i wysoką wilgotność względną, pozwala także na uzyskanie efektu ciągłej regulacji wydajności chłodniczej przy zastosowaniu prostego i efektywnego ekonomicznie układu chłodniczego sterowanego w najprostszy sposób w sposób dyskretny (włącz-wyłącz). Z racji stosowania pośredniego układu chłodzenia – należy liczyć się z możliwością obniżenia efektywności energetycznej układu. W niniejszym artykule podjęto zagadnienie oceny efektywności energetycznej układu chłodniczego obsługującego małą komorę składową o pojemności około 10 ton warzyw.
EN
The use of an indirect cooling system in refrigeration systems applied in vegetable or fruit cold storage chambers can be considered a long-term solution. It allows to obtain a stable temperature of the stored product close to the cryoscopic temperature, stable and high relative humidity, also allows to achieve the effect of continuous cooling capacity control using a simple and cost-effective refrigeration system controlled in the simplest way in a discreet way (on-off). Due to the use of an indirect cooling system – it may be taken into account the possibility of deterioration of the energy efficiency of the system. This article addresses the issue of energy efficiency evaluation of a refrigeration system applied in a small storage chamber of a capacity of approximately 10 tons of vegetables.
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