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1
Content available Reliability assessment for wind turbines considering the influence of wind speed using bayesian network
Su Ch., Fu Y.
Eksploatacja i Niezawodność
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2014
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Vol. 16, no. 1
1--8
PL
Niezawodność turbiny wiatrowej ma ogromne znaczenie dla gotowości i efektywności ekonomicznej instalacji wiatrowej. W niniejszym artykule zbudowano, w oparciu o sieci Bayesa (BN), model niezawodności turbiny wiatrowej uwzględniający wpływ prędkości wiatru. Przedstawiono Metodę Logiki Przyczynowości (Causal Logic Method, CLM), służącą do modelowania jakościowego, która łączy zalety drzewa błędów w odniesieniu do aspektów technicznych z atutami BN w odniesieniu do czynników środowiskowych i niepewności. Do kalkulacji ilościowych zaproponowano nową metodę dopasowania opartą na oczekiwaniach, w której dane z eksploatacji i opinie ekspertów łącznie pozwalają opisać niepewność rozkładów prawdopodobieństwa a priori. Wskaźnik niezawodności turbiny wiatrowej i jej elementów otrzymano posługując się algorytmem wnioskowania przybliżonego w połączeniu z dynamiczną dyskretyzacją zmiennych ciągłych. Dla zilustrowania proponowanej metody przedstawiono studium przypadku, którego wyniki wskazują, że prędkość wiatru jest ważnym czynnikiem niezawodności turbiny wiatrowej.
EN
The reliability of wind turbine is of great importance for the availability and economical efficiency of wind power system. In this article, a reliability model for wind turbine is built with Bayesian network (BN), in which the influence of wind speed is considered. Causal logic method (CLM) is presented for qualitative modeling, which combines the merits of fault tree in handling technical aspects and the strength of BN in dealing with environmental factors and uncertainty. A novel adjustment method based on expectation is proposed for quantitative calculation, by which historical data and expert judgment are integrated to describe the uncertainty in the prior probability distributions. An approximate inference algorithm combining with dynamic discretization of continuous variables is adopted to obtain the reliability index of wind turbine and its elements. A case study is given to illustrate the proposed method, and the results indicate that wind speed is an important factor for the reliability of wind turbine.
2
Content available remote Impact of spontaneously emitted photon on the dynamic behaviors of injection-locked semiconductor lasers
Fu Y., Chen J.
Optica Applicata
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2011
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Vol. 41, nr 1
15--27
EN
Starting from the mean-field rate equations describing the dynamic behaviors of the slave laser (SL) in the injection-locked master-slave semiconductor laser system (MSL), applying the perturbation method and the Cardan formula, analytical solutions to the evolutions of perturbations from the fixed point have been derived. The dynamic behaviors of the SL perturbed by a spontaneously emitted photon have been analyzed by using the above solutions. Finally, the phase space portraits with different phase between the spontaneously emitted photon and the injection field have also been investigated.
3
Content available remote Scale-up of slow rotary countercurrent chromatographic isolation of glucoraphanin and glucoraphenin from broccoli seeds and radish seeds
Fu Y., Du Q., Wang K.
Acta Chromatographica
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2008
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Vol. 20, no. 4
697-707
EN
A scaled-up SRCCC apparatus equipped with a 40-L column was constructed on the basis of separations of crude broccoli seed extract and crude radish seed extract using a conventional SRCCC instrument. Scaled-up separation of 500 g of crude broccoli seed extract with n -butanol-acetonitrile-10% (NH 4 ) 2 SO 4 aqueous solution 1:0.5:2 (υ/υ) as solvent system yielded 61.5 g glucoraphanin product of purity 91.2%. Separation of 500 g crude radish seed extract with the same solvents in the ratio 0.5:1:2 (υ/υ) afforded 26.7 g glucoraphenin product of purity 94.5%. Recovery of glucoraphanin and glucoraphenin from the crude extracts was 98.3 and 98.9%, respectively. The results demonstrated that this SRCCC technology is useful for separation of glucosinolates from plant extracts.
4
Content available remote Sensitivity-based stability evaluation of closed piping networks
Fu Y., Cai Y., Wu K.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2007
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Vol. 11, No 3
197-202
EN
Aiming at a closed-loop water system of HVAC engineering, the authors put forward an evaluation method of systems' stability based on sensitivity. It has three evaluating indexes: [alfa] - the summation of flow changes in other subcircuits influenced by resistance change in a certain subcircuit [Beta] - the summation of flow changes in a certain sub circuit influenced by resistance changes in other subcircuits; [gamma] - average [Beta] (or [alfa]) value of each subcircuit, reflecting the strength of regulating interference between subcircuits. The method is used to analyze the stability of a reverse return system (RRS) and a direct return system (DRS). The DRS subcircuit farthest from the heat source and the middle RRS are the least stable. Stability of the whole RRS is inferior to that of the DRS.
5
Content available remote Forecasting the energy-saving benefits of variable-speed pumps
Fu Y., Cai Y., Wu K.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2006
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Vol. 10, No 1
27-33
EN
By calculating the energy-saving benefits of a variable-speed pump, the relation between back pressure and energy-saving benefits is analyzed. Based on the energy-saving benefit calculation for four different pump types using a non-dimensional method, it is shown that when the non-dimensional back pressure, h, and the non-dimensional flow, Q, are equal, then the corresponding non-dimensional energy-saving benefit [omega] of variable-speed control are quite close each to other, thereby advancing a forecasting method of energy-saving benefits of variable-speed control. When the method is used to forecast the energy-saving benefits of pumps whose specific speed is between 15 and 190 and the flow - between 5 and 200 m3/h (subject to the condition h<; 0.9, Q> 0.5), the error will not exceed 6.55% and thus the method proves to be of reference value for the evaluation of the variable-speed energy-saving benefits of other pumps.
6
Content available remote Energy consumed by valves in conventional water systems and the application of a power-decentralization system
Fu Y., Cai Y., Zhang Z., Wu K.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2006
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Vol. 10, No 3
311-320
EN
The power consumption by valves of a conventional (i.e. power-centralized) water system is analyzed on the example of a water heating system in order to evaluate the extent of energy savings achievable in a power-decentralized system. The configuration and appli-cation of a power-decentralized system is briefly discussed.
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