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1
Content available New results from microalgae production and techniques
Grossmann J., Matthes S., Karwacki J., Kwidziński R., Tomaszewski A., Lackowski M., Cenian A.
Eco-Energetics : technologies, environment, law and economy
|
2019
|
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.
2
Content available remote Zagadnienia oceny efektywności energetycznej prototypowego układu chłodniczego obsługującego chłodnię składową warzyw
Butrymowicz D., Gagan J., Śmierciew K., Dudar A., Łukaszuk M., Mizera G., Karwacki J., Kwidziński R., Przybyliński T.
Instal
|
2018
|
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.
3
Content available Experimental observations of flow structures during DEP controlled boiling in a microchannel
Lackowski M., Kwidziński R., Karwacki J., Przybyliński T.
Archives of Thermodynamics
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2018
|
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.
4
Content available remote Theoretical analysis of latent thermal energy storage system with adsorption chiller
Karwacki J., Kwidziński R.
Polska Energetyka Słoneczna
|
2016
|
nr 1-4
59--64
EN
The paper deals with a theoretical analysis of using thermal energy storage filled with Phase Change Material (PCM) to optimise adsorption chiller application. The lumped model equations were developed to analyse heat transfer dynamics inside cooling installation. Model equations result from energy balances of the chiller, PCM thermal storage and heat load. Influence of heat transfer fluid flowrate control, heat capacity of the system components as well as heat losses to the ambient were taken into account. This study shows the great potential of PCM storage unit to optimize cooling systems.
5
Content available Methodology of heat transfer and flow resistance measurement for matrices of rotating regenerative heat exchangers
Butrymowicz D., Karwacki J., Kwidziński R., Śmierciew K., Gagan J., Przybyliński T., Skiepko T., Łapin M.
Chemical and Process Engineering
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2016
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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.
6
Badania eksperymentalne pracy dwufazowej pompy strumienicowej pracującej z izobutanem
Przybyliński T., Butrymowicz D., Karwacki J., Śmierciew K., Kwidziński R.
Chłodnictwo : organ Naczelnej Organizacji Technicznej
|
2014
|
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.
7
Badania własności termo-hydraulicznych około krytycznej strumienicy parowo-wodnej w aspekcie jej aplikacji w układach chłodniczych
Kwidziński R., Butrymowicz D., Karwacki J., Trela M., Śmierciew K.
Technika Chłodnicza i Klimatyzacyjna
|
2013
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nr 10
428--432
PL
W artykule przedstawiono wyniki doświadczalnych i teoretycznych badań własności przepływu w strumienicy parowo-wodnej. Strumienice tego rodzaju mogą znaleźć zastosowanie jako pompy w obiegach chłodniczych, zasilane częścią pary uzyskiwanej w generatorze pary napędowej. Przedstawione wyniki badań eksperymentalnych uzyskano dla strumienicy laboratoryjnej. Pomiędzy pomiarami zmieniano wartość przeciwciśnienia na wylocie strumienicy i/lub wydatek zasysanej wody. Na podstawie zebranych danych doświadczalnych wyznaczono współczynnik wnikania ciepła dla komory mieszania strumienicy, gdzie ma miejsce kondensacja pary napędowej w kontakcie z cieczą zasysaną.
EN
The article presents the results of experimental and theoretical studies of flow properties in the spotlight steam-water. Ejectors of this kind may be used as the pump in the cooling circuits, powered by steam generated in a part of the steam generator shaft. The experimental results were obtained for laboratory spotlight. Between measurements changed the value of the counter at the outlet jet and / or flow rate of water suction. Based on the collected experimental data was determined heat transfer coefficient for jet mixing chamber, where there is condensation driving in contact with the liquid aspirated.
8
Analiza teoretyczna pracy dwufazowej pompy strumienicowej dla węglowodorów
Przybyliński T., Butrymowicz D., Kwidziński R., Śmierciew K., Karwacki J.
Chłodnictwo : organ Naczelnej Organizacji Technicznej
|
2013
|
R. 48, nr 10
6--10
PL
W artykule przedstawiono model teoretyczny pracy dwufazowej pompy strumienicowej w zastosowaniu do układów chłodniczych. Wykonano obliczenia dla przykładowej geometrii strumienicy dla dwóch czynników roboczych: izobutanu oraz propanu. Wykazano, że dla izobutanu uzyskuje się korzystniejsza charakterystykę pracy takiej strumienicy w postaci zależności sprężu od stosunku zasysania.
EN
Theoretical model of operation of two-phase injector as a pump in refrigeration systems is presented. The results of calculations for selected geometries based on this model for hydrocarbons, i.e. isobutane and propane are presented. It was shown that the performance characteristic as relationship between pressure ratio and entrainment ratio is more profitable for isobutane rather than propane.
9
Content available A study of transcritical carbon dioxide cycles with heat regeneration
Trela M., Kwidziński R., Butrymowicz D.
Archives of Thermodynamics
|
2013
|
Vol. 34, no. 3
197--217
EN
The paper presents an efficiency analysis of two transcritical CO2 power cycles with regenerative heaters. For the proposed cycles, calculations of thermal efficiency are given for selected values of operating parameters. It was assumed that the highest working temperature and pressure are in the range from 600 to 700°C and 40 to 50 MPa, respectively. The purpose of the calculations was optimization of the pressure and mass flows in the regenerative heaters to achieve maximum cycle efficiency. It follows that for the assumed upper CO2 parameters, efficiency of 51-54% can be reached, which is comparable to the efficiency of a supercritical advanced power cycle considered by Dostal.
10
Content available A defnition of near-critical region based on heat capacity variation in transcritical heat exchangers
Trela M., Kwidziński R., Butrymowicz D.
Archives of Thermodynamics
|
2011
|
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.
11
Content available Control-volume-based model of the steam-water injector flow
Kwidziński R.
Archives of Thermodynamics
|
2010
|
Vol. 31, no. 1
45-59
EN
The paper presents equations of a mathematical model to calculate flow parameters in characteristic cross-sections in the steam-water injector. In the model, component parts of the injector (steam nozzle, water nozzle, mixing chamber, condensation wave region, diffuser) are treated as a series of connected control volumes. At first, equations for the steam nozzle and water nozzle are written and solved for known flow parameters at the injector inlet. Next, the flow properties in two-phase flow comprising mixing chamber and condensation wave region are determined from mass, momentum and energy balance equations. Then, water compression in diffuser is taken into account to evaluate the flow parameters at the injector outlet. Irreversible losses due to friction, condensation and shock wave formation are taken into account for the flow in the steam nozzle. In two-phase flow domain, thermal and mechanical nonequilibrium between vapour and liquid is modelled. For diffuser, frictional pressure loss is considered. Comparison of the model predictions with experimental data shows good agreement, with an error not exceeding 15% for discharge (outlet) pressure and 1 K for outlet temperature.
12
Content available Analysis of application of feed-water injector heaters to steam power plants
Trela M., Kwidziński R., Głuch J., Butrymowicz D.
Polish Maritime Research
|
2009
|
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.
13
Content available remote Feasibility study on application of steam injectors as feedwater heaters in supercritical Rankine cycle
Trela M., Kwidziński R., Głuch J., Butrymowicz D.
Archives of Thermodynamics
|
2009
|
Vol. 30, no. 4
133-147
EN
In the paper, a mathematical model of steam-water injector is presented. The model was used in heat balance calculations of Rankine cycle to examine the influence of novel injector feedwater heater system on efficiency of supercritical 600 MW coal-burned turbine unit. Also, the geometry of the injector system suitable for the considered Rankine cycle was determined. Analysis of cycle efficiency showed that application of steam-water injectors is most beneficial in the low pressure part of the Rankine cycle. Efficiency rise could be gained due to the absence of thermal degradation during the injector operation and due to its pumping work. Heat transfer coefficients for the injectors reach high values in the range of 190-806 kW/m[^2]K. Therefore, the heat transfer area in the system of injectors appeared to be smaller by a factor of 60 compared to equivalent shell-and-tube feedwater heaters. Size estimations of the new feedwater injectors shows that the overall dimensions and weight of the proposed injector system, consisting of several injectors connected in parallel, is significantly smaller compared to common shell-and-tube heaters. Exact proportions, however, will depend on detailed design of the entire system geometry.
14
Content available remote Control stage flow. Part I. Turbine nominal load
Lampart P., Szymaniak M, Kwidziński R
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
|
2008
|
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.
15
Content available remote Exergy analysis of losses in a two-phase steam-water injector
Trela M., Kwidziński R., Butrymowicz D.
Chemical and Process Engineering
|
2008
|
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%.
16
Content available remote Exergy analysis of steam-water injector performance
Trela M., Kwidziński R.
Archives of Thermodynamics
|
2008
|
Vol. 29, no. 1
41-58
EN
Exergy analysis is applied to estimate irreversible losses during operation to steam-water injector. Exergy destruction was determined for individual parts of the injector including steam nozzle, water nozzle and diffuser as well as for two-phase flow region comprising mixing chamber and condensation shock wave. Example calculations based on own experimental data showed that highest irreversible losses take place in two-phase flow region. Significant losses are also observed in the steam nozzle, while the losses in liquid-only flow in the water nozzle and diffuser are small and negligible. Exergy efficiency defined as outlet to inlet exergy ratio was also calculated for the injector and found to be in the range of 28-36%.
17
Content available remote Investigation of steam injector with variable throat cross-section
Kwidziński R., Trela M.
Archives of Thermodynamics
|
2007
|
Vol. 28, no. 1
3-14
EN
Increase of discharge pressure from steam injector by varying the throat cross-section of the mixing chamber with a moving needle is investigated experimentally and theoretically. Maximum discharge pressure was measured in two versions of the injector with the tapered needle inserted into the mixing chamber throat at varying deepness. Highest value of discharge pressure observed experimentally exceeded by about 35% the inlet steam pressure. This result is confirmed by theoretical consideration based on the momentum balance equation for the mixing chamber. In calculations, irreversible losses in the mixing chamber and Condensation shock wave are taken into account by total loss coefficient for which new correlation is proposed.
18
Wpływ geometrii strumienicy dwufazowej parowo-wodnej na charakterystyki jej pracy
Trela M., Kwidziński R.
Inżynieria i Aparatura Chemiczna
|
2006
|
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.
19
Termo-hydrauliczne własności nadkrytycznych strumienic dwufazowych para-woda
Trela M., Kwidziński R.
Systems : journal of transdisciplinary systems science
|
2004
|
Vol. 9, Sp. 2/2
1037-1043
PL
Referat dotyczy strumienie parowo-wodnych, które mogą spełniać role pompy bądź wymiennika ciepła. W pracy przedstawiono wyniki badań eksperymentalnych modelowej strumienicy, metodę wyznaczania współczynnika przejmowania ciepła oraz maksymalnego ciśnienia wylotowego ze strumienicy. Sformułowano model zjawiska oparty o bilans pędu obu fax z uwzględnieniem rzeczywistych strat nieodwracalności w komorze micsxania i dyfuzorze.
EN
The paper concerns experimental and theoretical studies of thermo-hydraulic performance of two-phase steam-water injector, in which the steam is a driving medium. In this type of injectors, the energy of the steam is used to push cold water from a lower to higher pressure, additionally heating it. Thus the steam injector can work as a pump or a heat exchanger. The steam injector consists generally of steam nozzle, water nozzle, mixing chamber and diffuser. The steam entering the injector is expanded and accelerated in converging-diverging steam nozzle. Having supersonic velocity and very low pressure, the steam enters the mixing chamber. Here, it meets liquid water which is drawn through the annular slot (the water nozzle). In the mixing chamber steam and water exchange heat, momentum (due to the temperature and velocity differences) and mass (due to condensation of steam on water). Usually the condensation process is terminated at the throat of the mixing chamber, followed by a rapid increase of pressure in this region (called the shock wave). Then, water is decelerated in the diffuser, which causes a further increase of pressure. The aim of the paper is to present the results of investigation of both heat transfer between the steam and water in the mixing chamber and maximum discharge pressure of the steam injector. The experimental Investigations of the steam injector comprised measurements of ptcssurCj temperature and void fraction profiles along the mixing chamber and diffuser. The mixing chamber and diffuser of test injector were made of transparent material. This allowed visual and photographic observations of flow structures in stroboscopic light as well as void fraction measurements by capacitance method. In theoretical part of the investigations, correlation for heat transfer coefficient was obtained. It is based on the dimensional analysis of one-dimensional two-fluid model of two-phase flow in the injector. The model of maximum discharge pressure from the steam injector was formulated applying the momentum balance equation. It takes into account irreversible losses due to the friction and temperature difference between both phases.
20
Content available remote Maximum discharge pressure of supercritical two-phase steam injector
Trela M., Kwidziński R., Buła M.
Archives of Thermodynamics
|
2004
|
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.
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