Relevant bibliographies by topics / Recirculation loop / Journal articles

Journal articles on the topic 'Recirculation loop'

To see the other types of publications on this topic, follow the link: Recirculation loop.
Author: Grafiati
Published: 8 June 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Recirculation loop.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Kim, Jaeheun, and Choongsik Bae. "Emission reduction through internal and low-pressure loop exhaust gas recirculation configuration with negative valve overlap and late intake valve closing strategy in a compression ignition engine." International Journal of Engine Research 18, no. 10 (February 1, 2017): 973–90. http://dx.doi.org/10.1177/1468087417692680.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
An investigation was carried out to examine the feasibility of replacing the conventional high-pressure loop/low-pressure loop exhaust gas recirculation with a combination of internal and low-pressure loop exhaust gas recirculation. The main objective of this alternative exhaust gas recirculation path configuration is to extend the limits of the late intake valve closing strategy, without the concern of backpressure caused by the high-pressure loop exhaust gas recirculation. The late intake valve closing strategy improved the conventional trade-off relation between nitrogen oxides and smoke emissions. The gross indicated mean effective pressure was maintained at a similar level, as long as the intake boosting pressure kept changing with respect to the intake valve closing timing. Applying the high-pressure loop exhaust gas recirculation in the boosted conditions yielded concern of the exhaust backpressure increase. The presence of high-pressure loop exhaust gas recirculation limited further intake valve closing retardation when the negative effect of increased pumping work cancelled out the positive effect of improving the emissions’ trade-off. Replacing high-pressure loop exhaust gas recirculation with internal exhaust gas recirculation reduced the burden of such exhaust backpressure and the pumping loss. However, a simple feasibility analysis indicated that a high-efficiency turbocharger was required to make the pumping work close to zero. The internal exhaust gas recirculation strategy was able to control the nitrogen oxides emissions at a low level with much lower O2 concentration, even though the initial in-cylinder temperature was high due to hot residual gas. Retardation of intake valve closing timing and intake boosting contributed to increasing the charge density; therefore, the smoke emission reduced due to the higher air–fuel ratio value exceeding 25. The combination of internal and low pressure loop loop exhaust gas recirculation with late intake valve closing strategy exhibited an improvement on the trade-off relation between nitrogen oxides and smoke emissions, while maintaining the gross indicated mean effective pressure at a comparable level with that of the high-pressure loop exhaust gas recirculation configuration.
2

Gautier, N., J. L. Aider, T. Duriez, B. R. Noack, M. Segond, and M. Abel. "Closed-loop separation control using machine learning." Journal of Fluid Mechanics 770 (April 10, 2015): 442–57. http://dx.doi.org/10.1017/jfm.2015.95.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
We present the first closed-loop separation control experiment using a novel, model-free strategy based on genetic programming, which we call ‘machine learning control’. The goal is to reduce the recirculation zone of backward-facing step flow at $\mathit{Re}_{h}=1350$ manipulated by a slotted jet and optically sensed by online particle image velocimetry. The feedback control law is optimized with respect to a cost functional based on the recirculation area and a penalization of the actuation. This optimization is performed employing genetic programming. After 12 generations comprised of 500 individuals, the algorithm converges to a feedback law which reduces the recirculation zone by 80 %. This machine learning control is benchmarked against the best periodic forcing which excites Kelvin–Helmholtz vortices. The machine learning control yields a new actuation mechanism resonating with the low-frequency flapping mode instability. This feedback control performs similarly to periodic forcing at the design condition but outperforms periodic forcing when the Reynolds number is varied by a factor two. The current study indicates that machine learning control can effectively explore and optimize new feedback actuation mechanisms in numerous experimental applications.
3

Alekseev, É. I., E. N. Bazarov, V. P. Gubin, V. G. Kovalenko, A. I. Sazonov, and N. I. Starostin. "Recirculation fiber loop interferometer with a Faraday reflector." Technical Physics Letters 28, no. 11 (November 2002): 949–51. http://dx.doi.org/10.1134/1.1526893.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Araiza-Martínez, Enrique, Javier Ortiz-Villafuerte, and Rogelio Castillo-Durán. "A detailed BWR recirculation loop model for RELAP." Nuclear Engineering and Design 311 (January 2017): 1–8. http://dx.doi.org/10.1016/j.nucengdes.2016.11.006.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Markina, L. M., N. Yr Zholobenko, and S. Yr Ushcats. "Investigation of the influence of the physicochemical characteristics of waste on the quality of liquid fuel products from them, obtained by multi-loop recirculation pyrolysis." Journal of Achievements in Materials and Manufacturing Engineering 1, no. 106 (May 1, 2021): 20–33. http://dx.doi.org/10.5604/01.3001.0015.0526.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Purpose: To study the properties of MSW generated in Ukraine in order to ensure their most efficient processing using the multi-loop recirculation pyrolysis technology in order produce a liquid fuel product. Design/methodology/approach: The problem' study of MSW accumulation in the world countries was carried out on the basis scientific databases PubMed, ScienceDirect, Mendeley, ResearchGate, Google Scholar for the corresponding keywords. The MSW properties generated in Ukraine were determined in accordance with the current standards to determine the specific properties of materials. For the experimental study, 3 types of solid organic waste mixtures were compiled, the composition of which characterizes the variable data on the accumulation of household and industrial waste of Ukraine. The quantity and quality of the liquid product obtained was determined using certified equipment. Findings: The tests revealed that the composition of the solid organic waste mixture when disposing of them by the multi-loop recirculation pyrolysis method has little effect the composition and properties of the obtained liquid hydrocarbon product; the total time of complete degradation for different mixtures of composite materials (mixtures of polymeric substances) is 180-250 min; the correct selection of the temperature of the circulation system makes it possible to produce a gaseous or liquid product which can then be used as an alternative fuel. Research limitations/implications: Current study of solid organic waste degradation was carried out by the multi-loop recirculation pyrolysis method. The experimental waste mixtures did not contain very wet waste of small fractions. Practical implications: The technology of circulating pyrolysis makes it possible to change the qualitative and quantitative composition of the obtained liquid hydrocarbon product, which is a potential fuel, irrespective of the composition of the solid organic waste mixture.Originality/value: It has been experimentally established that the quality of the liquid hydrocarbon product obtained by the multi-loop recirculation pyrolysis process does not depend on the composition of the solid organic waste mixture, but depends on the process' duration and the third circuit' temperature of the multi-loop recirculation system.
6

Liu, Yu, and Shibao Wu. "Proposed Scheme for Ultra-Flat Optical Frequency Comb Generation Based on Dual-Drive Mach–Zehnder Modulators and Bidirectional Recirculating Frequency Shifting in Single Loop." Photonics 9, no. 8 (July 24, 2022): 514. http://dx.doi.org/10.3390/photonics9080514.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Recirculating frequency shifting has attracted much attention for its advantages in the generation of the flexible and high-quality optical frequency comb. A new scheme of ultra-flat optical frequency comb generation system based on single-loop bidirectional recirculating frequency shift is proposed and studied in this paper. The generation system employs two pairs of dual-drive Mach–Zehnder modulators and several polarization devices. Compared with the method of single-loop unidirectional recirculation frequency shift, under the same cycles, the number of comb lines generated by the proposed method is doubled, and the generated optical frequency combs have less noise accumulation and better flatness. The theoretical model is established, and the proposed scheme is verified by software simulation. A 111-line optical frequency comb with the spacing of 12.5 GHz, the flatness of 0.76 dB, and the optical signal-to-noise ratio of 27.39 dB was obtained by adopting the proposed scheme.
7

van Benthum, W. A. J., R. G. J. M. van der Lans, M. C. M. van Loosdrecht, and J. J. Heijnen. "Bubble recirculation regimes in an internal-loop airlift reactor." Chemical Engineering Science 54, no. 18 (September 1999): 3995–4006. http://dx.doi.org/10.1016/s0009-2509(99)00097-4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Sheintuch, Moshe, and Olga Nekhamkina. "Comparison of flow-reversal, internal-recirculation and loop reactors." Chemical Engineering Science 59, no. 19 (October 2004): 4065–72. http://dx.doi.org/10.1016/j.ces.2004.04.037.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Braun, D., and W. Gujer. "Reactive tracers reveal hydraulic and control instabilities in full-scale activated sludge plant." Water Science and Technology 57, no. 7 (April 1, 2008): 1001–7. http://dx.doi.org/10.2166/wst.2008.210.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
The hydraulic characteristics of aeration tanks in WWTPs have a major impact on the degradation of pollutants, as well as on the control of the aeration. In particular in long reactors, which are not separated by baffles, hydraulic shortcuts or large scale recirculation can lead to a loss of performance. This work demonstrates that reactive tracers such as ammonium and oxygen can be used to investigate the hydraulics of aeration tanks in detail. With the use of electrochemical sensors it is possible to investigate effects in a broad range of time scales. In the present case study a slow oscillation of the aeration control loop was investigated. Large scale recirculation in the aeration tank and fast fluctuations of the ammonium concentrations close to the oxygen sensor were identified as the cause of these oscillations. Both, the recirculation as well as the fluctuation of the ammonium have a substantial influence on the performance of the aeration tank and the aeration control loop.
10

Kalmani, S. D., A. V. Joshi, G. Majumder, N. K. Mondal, and R. R. Shinde. "Design validation and performance of closed loop gas recirculation system." Journal of Instrumentation 11, no. 11 (November 21, 2016): C11026. http://dx.doi.org/10.1088/1748-0221/11/11/c11026.

Full text
APA, Harvard, Vancouver, ISO, and other styles
11

Lapa, Rui A. S., José L. F. C. Lima, Boaventura F. Reis, and João L. M. Santos. "Continuous sample recirculation in an opened-loop multicommutated flow system." Analytica Chimica Acta 377, no. 1 (December 1998): 103–10. http://dx.doi.org/10.1016/s0003-2670(98)00561-3.

Full text
APA, Harvard, Vancouver, ISO, and other styles
12

IKEDA, Takashi, Atsuo YAMANOUCHI, and Masanori NAITOH. "BWR Recirculation Line Break Simulation Tests at Two Bundle Loop." Journal of Nuclear Science and Technology 22, no. 4 (April 1985): 249–68. http://dx.doi.org/10.1080/18811248.1985.9735656.

Full text
APA, Harvard, Vancouver, ISO, and other styles
13

Pavko, A., and M. Charles. "Liquid circulation and mixing in tower fermenters with recirculation loop." Biotechnology Letters 10, no. 8 (August 1988): 537–42. http://dx.doi.org/10.1007/bf01027125.

Full text
APA, Harvard, Vancouver, ISO, and other styles
14

Caspari, Stefan, Leonie S. Schwärzel, Anna M. Jungmann, Nicole Schmoll, Frederik Seiler, Ralf M. Muellenbach, Marcin Krawczyk, et al. "A Novel Mock Circuit to Test Full-Flow Extracorporeal Membrane Oxygenation." Membranes 12, no. 5 (April 30, 2022): 493. http://dx.doi.org/10.3390/membranes12050493.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Extracorporeal membrane oxygenation (ECMO) has become an important therapeutic approach in the COVID-19 pandemic. The development and research in this field strongly relies on animal models; however, efforts are being made to find alternatives. In this work, we present a new mock circuit for ECMO that allows measurements of the oxygen transfer rate of a membrane lung at full ECMO blood flow. The mock utilizes a large reservoir of heparinized porcine blood to measure the oxygen transfer rate of the membrane lung in a single passage. The oxygen transfer rate is calculated from blood flow, hemoglobin value, venous saturation, and post-membrane arterial oxygen pressure. Before the next measuring sequence, the blood is regenerated to a venous condition with a sweep gas of nitrogen and carbon dioxide. The presented mock was applied to investigate the effect of a recirculation loop on the oxygen transfer rate of an ECMO setup. The recirculation loop caused a significant increase in post-membrane arterial oxygen pressure (paO2). The effect was strongest for the highest recirculation flow. This was attributed to a smaller boundary layer on gas fibers due to the increased blood velocity. However, the increase in paO2 did not translate to significant increases in the oxygen transfer rate because of the minor significance of physically dissolved oxygen for gas transfer. In conclusion, our results regarding a new ECMO mock setup demonstrate that recirculation loops can improve ECMO performance, but not enough to be clinically relevant.
15

Галушин, С. Я., and Д. Н. Шаманов. "Hydrogen and oxygen recirculation control system for an electric power plant based on an electrochemical generator." MORSKIE INTELLEKTUAL`NYE TEHNOLOGII), no. 4(50) (November 23, 2020): 116–22. http://dx.doi.org/10.37220/mit.2020.50.4.050.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Развитие водородной энергетики ведет к увеличению использования электрохимических генераторов (ЭХГ) в морских транспортных средствах в качестве вспомогательных и основных энергоустановок. Топливом для таких энергетических установок являются водород и кислород. Важной для таких энергетических установок является экологическая составляющая При прямом преобразовании химической энергии топлива в электрическую в топливных элементах, побочным продуктом реакции является только вода. В статье рассматривается система управления рециркуляцией рабочих газов - водорода и кислорода в электрохимическом генераторе. Система управления состоит из двух независимых субблоков - контура рециркуляции водорода и контура рециркуляции кислорода. Каждый субблок, работающий по своему алгоритму, построен на программируемом логическом контроллере и управляемой арматуре. В статье также приведены режимы работы системы управления рециркуляцией газов. The development of hydrogen energy increases electrochemical generators (ECG) using in marine vehicles as an auxiliary and main power plants. The fuel for such power plants are hydrogen and oxygen. The environmental component is important for such power plants. When the chemical energy of a fuel is directly converted into electrical energy in fuel cells, there are only water is a by-product of the reaction. The article discusses the control system of the working gases recirculation - hydrogen and oxygen in an electrochemical generator. The control system consists of two independent subunits - a hydrogen recirculation loop and an oxygen recirculation loop. Each subunit is built on a programmable logic controller and controlled armature, working according to its own algorithm. The article also describes the operating modes of the gas recirculation control system.
16

Salzano, Ernesto, Martino Di Serio, and Elio Santacesaria. "The role of recirculation loop on the risk of ethoxylation processes." Journal of Loss Prevention in the Process Industries 20, no. 3 (May 2007): 238–50. http://dx.doi.org/10.1016/j.jlp.2007.03.016.

Full text
APA, Harvard, Vancouver, ISO, and other styles
17

Salehi, Rasoul, Anna Stefanopoulou, and Bruce Vernham. "Diesel air path control using pressure difference: Pumping loss and aging considerations." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 10 (July 23, 2018): 2421–31. http://dx.doi.org/10.1177/0954407018784696.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Pressure difference across the exhaust and intake manifolds ([Formula: see text] P) is a crucial variable to control the pumping loss and cylinder charge dilution through the exhaust gas recirculation in a diesel engine. This paper presents a novel architecture for controlling [Formula: see text] P and the engine-out NO x emissions, which increases the controller tolerance to engine components aging. The architecture has an internal control loop, designed as a two-input two-output controller, to coordinate the exhaust gas recirculation and variable geometry turbine valves. Using feedback from [Formula: see text] P and the estimated cylinder oxygen ratio [Formula: see text] cyl, the two-input two-output controller regulates the pumping loss and the engine NO x emissions. To reduce high turbo lag and its associated slow air–fuel ratio ([Formula: see text]) response, which are inherent features of a [Formula: see text] P-based control strategy, the two-input two-output linear quadratic controller is tuned such that [Formula: see text] is also regulated, but only during fast transients. An external loop is supplementing the core two-input two-output controller correcting the internal loop set points to reduce the effects of [Formula: see text] cyl estimation errors on NO x control and ensure [Formula: see text] stays above a minimum value, [Formula: see text] min, critical for smoke emissions. As a feature of the proposed control system, direct feedback from [Formula: see text] P increases pumping loss robustness to common degradation in diesel engines, namely, turbine efficiency and diesel particulate filter blockage due to ash deposit, compared to a conventional boost pressure–based controller. Also, it is shown that the input–output coupling structure of the proposed two-input two-output controller and use of the NO x feedback mitigate effects of exhaust gas recirculation fouling and associated exhaust gas recirculation valve saturation on increase in NO x emission.
18

Cheng, Li, Pavlos Dimitriou, William Wang, Jun Peng, and Abdel Aitouche. "A novel fuzzy logic variable geometry turbocharger and exhaust gas recirculation control scheme for optimizing the performance and emissions of a diesel engine." International Journal of Engine Research 21, no. 8 (October 31, 2018): 1298–313. http://dx.doi.org/10.1177/1468087418809261.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Variable geometry turbocharger and exhaust gas recirculation valves are widely installed on diesel engines to allow optimized control of intake air mass flow and exhaust gas recirculation ratio. The positions of variable geometry turbocharger vanes and exhaust gas recirculation valve are predominantly regulated by dual-loop proportional–integral–derivative controllers to achieve predefined set-points of intake air pressure and exhaust gas recirculation mass flow. The set-points are determined by extensive mapping of the intake air pressure and exhaust gas recirculation mass flow against various engine speeds and loads concerning engine performance and emissions. However, due to the inherent nonlinearities of diesel engines and the strong interferences between variable geometry turbocharger and exhaust gas recirculation, an extensive map of gains for the P, I, and D terms of the proportional–integral–derivative controllers is required to achieve desired control performance. The present simulation study proposes a novel fuzzy logic control scheme to determine appropriate positions of variable geometry turbocharger vanes and exhaust gas recirculation valve in real-time. Once determined, the actual positions of the vanes and valve are regulated by two local proportional–integral–derivative controllers. The fuzzy logic control rules are derived based on an understanding of the interactions among the variable geometry turbocharger, exhaust gas recirculation, and diesel engine. The results obtained from an experimentally validated one-dimensional transient diesel engine model showed that the proposed fuzzy logic control scheme is capable of efficiently optimizing variable geometry turbocharger and exhaust gas recirculation positions under transient engine operating conditions in real-time. Compared to the baseline proportional–integral–derivative controllers approach, both engine’s efficiency and total turbo efficiency have been improved by the proposed fuzzy logic control scheme while NOx and soot emissions have been significantly reduced by 34% and 82%, respectively.
19

Vasilescu, M. V., O. Volintiru, Alexey Ivanovich Epikhin, and T. Toriya. "CLOSED-LOOP MARINE ENGINE OPERATION WITH ZERO EMISSIONS OF HARMFUL COMBUSTION PRODUCTS." Operation of Maritime Transport, no. 4 (March 9, 2023): 203–7. http://dx.doi.org/10.34046/aumsuomt105/38.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
In the modern world, the problem of environmental pollution with various toxic emissions is growing more and more. Exhaust or exhaust gases of internal combustion engines are one of those man-made factors. All countries impose restrictions on the concentration of hazardous substances, for example: Euro - for cars, Tier and Stage - for heavy equipment and MARPOL-73/78, which regulates emissions from maritime transport. The situation is extremely acute for marine vessels, since engines of impressive power that operate for a long period are difficult to adapt to stringent environmental requirements. The purpose of the article, based on open sources, is to evaluate the prospects for the development of internal combustion engines with an exhaust gas recirculation system to minimize the amount of toxic emissions into the atmosphere. The development of technologies that allow for the recirculation of exhaust gases in ship conditions is quite promising. The installation of such equipment will significantly reduce emissions into the environment. Keywords: environment, exhaust gases, toxic emissions, internal combustion engines
20

Van den Heuvel, J. C., P. G. Verschuren, and S. P. P. Ottengraf. "Acceleration of mass transfer in loop reactors." Water Science and Technology 36, no. 1 (July 1, 1997): 311–19. http://dx.doi.org/10.2166/wst.1997.0069.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Gas bubbles entrapped in biocatalyst particles subjected to hydrostatic pressure oscillations, e.g. during recirculation in loop reactors, will induce intraparticle liquid flows, and thereby enhance mass transfer in excess of diffusion. This ‘breathing particle’ mechanism was demonstrated in methanogenic granules, and led to a typical activity increase of 13% compared with static pressure conditions. From these experimental results and model predictions, it is concluded that convective acceleration of mass transfer in gas-producing systems offers interesting perspectives for the optimisation of biofilm processes in loop reactors. Development of special carrier materials with a central gas-filled cavity could lead to a novel type of bioreactor in which liquid flow through the biocatalyst is decisive.
21

Jatana, Gurneesh S., and Brian C. Kaul. "Characterization of temporal variations and feedback timescales of exhaust gas recirculation gas properties using high-speed diode laser absorption spectroscopy for next-cycle control of cyclic variability." International Journal of Engine Research 20, no. 8-9 (October 11, 2018): 945–52. http://dx.doi.org/10.1177/1468087418805654.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Dilute combustion offers efficiency gains in boosted gasoline direct injection engines both through knock-limit extension and thermodynamic advantages (i.e. the effect of γ on cycle efficiency), but is limited by cyclic variability at high dilution levels. Past studies have shown that the cycle-to-cycle dynamics are a combination of deterministic and stochastic effects. The deterministic causes of cyclic variations, which arise from feedback due to exhaust gas recirculation, imply the possibility of using active control strategies for dilution limit extension. While internal exhaust gas recirculation will largely provide a next-cycle effect (short-timescale feedback), the feedback of external exhaust gas recirculation will have an effect after a delay of several cycles (long timescale). Therefore, control strategies aiming to improve engine stability at dilution limit may have to account for both short- and long-timescale feedback pathways. This study shows the results of a study examining the extent to which variations in exhaust gas recirculation composition are preserved along the exhaust gas recirculation flow path and thus the relative importance and information content of the long-timescale feedback pathway. To characterize the filtering or retention of cycle-resolved feedback information, high-speed (1–5 kHz) CO2 concentration measurements were performed simultaneously at three different locations along the low-pressure external exhaust gas recirculation loop of a four-cylinder General Motors gasoline direct injection engine using a multiplexed two-color diode laser absorption spectroscopy sensor system during steady-state and transient engine operation at various exhaust gas recirculation levels. It was determined that cycle-resolved feedback propagates through internal residual gases but is filtered out by the low-pressure exhaust gas recirculation flow system and do not reach the intake manifold. Intermediate variations driven by flow rate and compositional changes are also distinguished and identified.
22

Singh, Rajveer, Deepika Chauhan, Alanna Fogarty, Md Rasheduzzaman, and Patrick L. Gurian. "Practitioners’ Perspective on the Prevalent Water Quality Management Practices for Legionella Control in Large Buildings in the United States." Water 14, no. 4 (February 21, 2022): 663. http://dx.doi.org/10.3390/w14040663.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Managing building water systems is complicated by the need to maintain hot water temperatures high enough to control the growth of Legionella spp. while minimizing the risk of scalding. This study assessed water quality management practices in large buildings in the United States. Surveys conducted with building water quality managers found that more than 85% of buildings have hot water temperatures that are consistent with scald risk mitigation guidelines (i.e., <122 °F/50 °C). However, nearly two thirds and three quarters of buildings do not comply with the common temperature guidance for opportunistic pathogen control, i.e., water heater setpoint > 140 °F (60 °C) and recirculation loop > 122 °F (50 °C), respectively; median values for both setpoint and recirculation loop temperatures are 10 °F (6 °C) or more below temperatures recommended for opportunistic pathogen control. These observations suggest that many buildings are prone to Legionella spp. risk. The study also found that 27% of buildings do not comply with guidelines for time to equilibrium hot water temperature, over 33% fail to monitor temperature in the recirculation loop, more than 70% fail to replace or disinfect showerheads, more than 40% lack a written management plan, and only a minority conduct any monitoring of residual disinfectant levels or microbiological quality. Given the rise in Legionellosis infections in recent years, coupled with highlighted water quality concerns because of prolonged water stagnation in plumbing, such as in buildings closed due to COVID-19, current management practices, which appear to be focused on scald risk, may need to be broadened to include greater attention to control of opportunistic pathogens. To accomplish this, there is a need for formal training and resources for facility managers.
23

Yamashita, Akira, Hisashi Ohki, Koichiro Nakatani, and Terutoshi Tomoda. "OS2-7 Recirculation control logic for Diesel Low Pressure Loop EGR System(OS2 EGR combustion,Organized Session Papers)." Proceedings of the International symposium on diagnostics and modeling of combustion in internal combustion engines 2012.8 (2012): 110–15. http://dx.doi.org/10.1299/jmsesdm.2012.8.110.

Full text
APA, Harvard, Vancouver, ISO, and other styles
24

NODA, Hiroshi, Tadashi NARABAYASHI, and Yuuji TAKAHASHI. "Countermeasure against Thermal Fatigue Crack of Primary Loop Recirculation Pump in BWR." Transactions of the Atomic Energy Society of Japan 7, no. 4 (2008): 338–49. http://dx.doi.org/10.3327/taesj.j07.042.

Full text
APA, Harvard, Vancouver, ISO, and other styles
25

Hümmeler, A., and R. Holz. "Recirculation loop replacement at boiling water reactors / Austausch von Treibwasserschleifen in Siedewasseranlagen." Kerntechnik 52, no. 2 (February 1, 1988): 131–35. http://dx.doi.org/10.1515/kern-1988-520223.

Full text
APA, Harvard, Vancouver, ISO, and other styles
26

Yang, Min, Hongya Wang, Lulu Wang, Lei Shen, Lei Zhang, Jie Luo, Jing Du, and Jian Wang. "MIMO-free OAM-MDM transmission with a ring-core fiber recirculation loop." Optical Fiber Technology 81 (December 2023): 103552. http://dx.doi.org/10.1016/j.yofte.2023.103552.

Full text
APA, Harvard, Vancouver, ISO, and other styles
27

Maldonado, Bryan P., Nan Li, Ilya Kolmanovsky, and Anna G. Stefanopoulou. "Learning reference governor for cycle-to-cycle combustion control with misfire avoidance in spark-ignition engines at high exhaust gas recirculation–diluted conditions." International Journal of Engine Research 21, no. 10 (June 26, 2020): 1819–34. http://dx.doi.org/10.1177/1468087420929109.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Cycle-to-cycle feedback control is employed to achieve optimal combustion phasing while maintaining high levels of exhaust gas recirculation by adjusting the spark advance and the exhaust gas recirculation valve position. The control development is based on a control-oriented model that captures the effects of throttle position, exhaust gas recirculation valve position, and spark timing on the combustion phasing. Under the assumption that in-cylinder pressure information is available, an adaptive extended Kalman filter approach is used to estimate the exhaust gas recirculation rate into the intake manifold based on combustion phasing measurements. The estimation algorithm is adaptive since the cycle-to-cycle combustion variability (output covariance) is not known a priori and changes with operating conditions. A linear quadratic regulator controller is designed to maintain optimal combustion phasing while maximizing exhaust gas recirculation levels during load transients coming from throttle tip-in and tip-out commands from the driver. During throttle tip-outs, however, a combination of a high exhaust gas recirculation rate and an overly advanced spark, product of the dynamic response of the system, generates a sequence of misfire events. In this work, an explicit reference governor is used as an add-on scheme to the closed-loop system in order to avoid the violation of the misfire limit. The reference governor is enhanced with model-free learning which enables it to avoid misfires after a learning phase. Experimental results are reported which illustrate the potential of the proposed control strategy for achieving an optimal combustion process during highly diluted conditions for improving fuel efficiency.
28

Zhang, Yunfan, Guoxiang Lu, Hongming Xu, and Ziyang Li. "Tuneable model predictive control of a turbocharged diesel engine with dual loop exhaust gas recirculation." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 8 (October 6, 2017): 1105–20. http://dx.doi.org/10.1177/0954407017726944.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
The air path of a turbocharged diesel engine is a multi-input multi-output (MIMO) system with strong nonlinearity, coupling effect, delay and actuator constraints. This makes the design and tuning of the controller complex. In this paper, a tuneable model predictive control (TMPC) controller for a diesel engine’s air path with dual loop exhaust gas recirculation (DLEGR) is presented. The objective is to regulate the intake manifold pressure and exhaust gas recirculation (EGR) mass flow in each loop to meet the time-varying setpoints through coordinated control of the variable geometry turbocharger (VGT) and EGR valves. The TMPC controller adopts the design framework of an MPC controller. This controller is also able to provide a map-based switching scheme for the local controller and the controller’s weightings. A comparison between the TMPC controller and a conventional PID controller is conducted on a validated real-time engine model. The simulation results show that the TMPC controller achieves lower overshoot, faster response and a shorter settling time on the manipulated objects. These improvements are beneficial for obtaining lower fuel consumption. In order to test the capability of the TMPC controller, it is validated on a hardware in the loop (HIL) platform. The results show that the agreement between the simulation and the actual ECU’s response is good.
29

Kaupert, Kevin A., and Thomas Staubli. "The Unsteady Pressure Field in a High Specific Speed Centrifugal Pump Impeller—Part II: Transient Hysteresis in the Characteristic." Journal of Fluids Engineering 121, no. 3 (September 1, 1999): 627–32. http://dx.doi.org/10.1115/1.2823515.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Hysteresis in a pump characteristic results from instability phenomena involving complex three dimensional flow with recirculation. The unsteady flow field on the top and bottom branches of a hysteresis loop in a high specific speed (ωs = 1.7) centrifugal pump characteristic was experimentally evaluated. A hypothesis for recirculation zones and prerotation as power dissipaters is proposed for explaining the discrepancy in the pressure and shaft power hysteresis. The experimental investigation was performed in both the rotating and stationary frame. In the rotating frame 25 miniature pressure transducers mounted in an impeller blade passage were sampled with a telemetry system. In the stationary frame a fast response probe was implemented. The changing impeller flow field manifested itself between the two branches of the hysteresis with increasing stochastic pressure fluctuations. Using this information the position, size, and strength of the impeller recirculation was quantitatively determined. Theoretically the rate of change of useful hydraulic power in the hysteresis regime during transient pump operation was found to be a function of throttling rate. Quasi-steady behavior existed for slow throttling, |dφ/dt| < 0.005 s−1. A second-order nonlinear dependence on the throttle rate was determined for the change of useful flow power during the commencement/cessation of the impeller recirculation.
30

Bolpaire, S., and J. P. Barrand. "Experimental Study of the Flow in the Suction Pipe of a Centrifugal Pump at Partial Flow Rates in Unsteady Conditions." Journal of Pressure Vessel Technology 121, no. 3 (August 1, 1999): 291–95. http://dx.doi.org/10.1115/1.2883705.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
The operational range and the performances of pumps are limited by the occurrence of backflow and prerotation in the suction pipe as the flow rate is reduced. This paper presents the study of static pressure measurements and visualizations in the suction pipe, near the inlet of a centrifugal pump, at partial flow rates, in steady conditions, and during a fast start-up of the pump. The tests were carried out in water on the DERAP© test loop of the ENSAM Lille laboratory. Standard methods allowed to determine the recirculation critical flow rate. A visualization method showed that the axial extent of the recirculation and the prerotation with the flow rate is considerably reduced during a fast start-up compared to steady conditions.
31

LOPEZ, J. M., Y. D. CUI, F. MARQUES, and T. T. LIM. "Quenching of vortex breakdown oscillations via harmonic modulation." Journal of Fluid Mechanics 599 (March 6, 2008): 441–64. http://dx.doi.org/10.1017/s002211200800027x.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Vortex breakdown is a phenomenon inherent to many practical problems, such as leading-edge vortices on aircraft, atmospheric tornadoes, and flame-holders in combustion devices. The breakdown of these vortices is associated with the stagnation of the axial velocity on the vortex axis and the development of a near-axis recirculation zone. For large enough Reynolds number, the breakdown can be time-dependent. The unsteadiness can have serious consequences in some applications, such as tail-buffeting in aircraft flying at high angles of attack. There has been much interest in controlling the vortex breakdown phenomenon, but most efforts have focused on either shifting the threshold for the onset of steady breakdown or altering the spatial location of the recirculation zone. There has been much less attention paid to the problem of controlling unsteady vortex breakdown. Here we present results from a combined experimental and numerical investigation of vortex breakdown in an enclosed cylinder in which low-amplitude modulations of the rotating endwall that sets up the vortex are used as an open-loop control. As expected, for very low amplitudes of the modulation, variation of the modulation frequency reveals typical resonance tongues and frequency locking, so that the open-loop control allows us to drive the unsteady vortex breakdown to a prescribed periodicity within the resonance regions. For modulation amplitudes above a critical level that depends on the modulation frequency (but still very low), the result is a periodic state synchronous with the forcing frequency over an extensive range of forcing frequencies. Of particular interest is the spatial form of this forced periodic state: for modulation frequencies less than about twice the natural frequency of the unsteady breakdown, the oscillations of the near-axis recirculation zone are amplified, whereas for modulation frequencies larger than about twice the natural frequency the oscillations of the recirculation zone are quenched, and the near-axis flow is driven to the steady axisymmetric state. Movies are available with the online version of the paper.
32

Baruh Susskind, Suzanne, Claudio Floridia, Fabio Simoes, Maria Aparecida Martinez, and Monica de Lacerda Rocha. "Experimental and Theoretical Study of Polarization Dependent Loss in a Optical Recirculation Loop." IEEE Latin America Transactions 9, no. 1 (March 2011): 759–65. http://dx.doi.org/10.1109/tla.2011.5876416.

Full text
APA, Harvard, Vancouver, ISO, and other styles
33

Dzianik, František, and Štefan Gužela. "Basic Technological Parameters of the Activation Process for Two Bioreactor Configurations." Strojnícky časopis - Journal of Mechanical Engineering 73, no. 1 (May 1, 2023): 43–54. http://dx.doi.org/10.2478/scjme-2023-0004.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Abstract Technological parameters of the activation process in wastewater treatment plant activation systems are analyzed for basic bioreactor configurations, for the chemostat and for the plug flow, both with the recirculation of concentrated activated sludge. The first type of bioreactors represents conventional aerated tanks, but also loop bioreactors. The second type of bioreactors includes, for example, oxidation ditches. The paper presents an evaluation of the basic technological parameters of the activation process for the two mentioned configurations of bioreactor systems with recirculation of concentrated activated sludge. In addition, a new relation for sludge age evaluation is proposed for an activation system with a plug flow bioreactor. The article also provides examples of connections between the values of the technological parameters of the activation process for the two analyzed types of bioreactor systems.
34

Bougaenko, S. E., E. Yu Rivkin, and B. S. Rodchenkov. "Strength Aspects of Safety and Life Extension of RBMK Reactors." Journal of Pressure Vessel Technology 113, no. 2 (May 1, 1991): 141–44. http://dx.doi.org/10.1115/1.2928738.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
RBMK channel power reactors belong to the one-loop boiling water reactors with graphite as a moderator. Equipment, pipelines and core elements are the main components of the coolant recirculation circuit. Analysis in terms of fracture mechanics shows that the circuit elements conform to the “leak-before-break” criterion, with the pipelines and equipment keeping their availability during the whole design operation period. The core is a critical component for the circuit availability.
35

Johansson, Andreas, Filip Johnsson, and Bengt-Åke Andersson. "The Performance of a Loop Seal in a CFB Boiler." Journal of Energy Resources Technology 128, no. 2 (January 31, 2006): 135–42. http://dx.doi.org/10.1115/1.2199567.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
High in-bed heat transfer and low corrosive environment imply that the loop seal of a circulating fluidized bed (CFB) boiler is an advantageous location for superheaters. In order to increase the knowledge on the flow pattern and the heat transfer distribution to the tubes within a loop seal, measurements were performed in the loop seal of a 30MW CFB boiler as well as in a 1∕3 scaled-down seal operated according to simplified scaling laws. The scale model measurements show that the solids recirculation flux can be maintained with a substantial decrease of the fluidization flow in the seal compared to that currently used at full load conditions. It was also possible to significantly decrease the fraction of the bottom of the seal that was fluidized without affecting the solids flux through the seal. A gradient in the solids flow were detected in the vertical direction.
36

Debski, Pawel, Karolina Sklodowska, Jacek Michalski, Piotr Korczyk, Miroslaw Dolata, and Slawomir Jakiela. "Continuous Recirculation of Microdroplets in a Closed Loop Tailored for Screening of Bacteria Cultures." Micromachines 9, no. 9 (September 17, 2018): 469. http://dx.doi.org/10.3390/mi9090469.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Emerging microfluidic technology has introduced new precision controls over reaction conditions. Owing to the small amount of reagents, microfluidics significantly lowers the cost of carrying a single reaction. Moreover, in two-phase systems, each part of a dispersed fluid can be treated as an independent chemical reactor with a volume from femtoliters to microliters, increasing the throughput. In this work, we propose a microfluidic device that provides continuous recirculation of droplets in a closed loop, maintaining low consumption of oil phase, no cross-contamination, stabilized temperature, a constant condition of gas exchange, dynamic feedback control on droplet volume, and a real-time optical characterization of bacterial growth in a droplet. The channels (tubing) and junction cubes are made of Teflon fluorinated ethylene propylene (FEP) to ensure non-wetting conditions and to prevent the formation of biofilm, which is particularly crucial for biological experiments. We show the design and operation of a novel microfluidic loop with the circular motion of microdroplet reactors monitored with optical sensors and precision temperature controls. We have employed the proposed system for long term monitoring of bacterial growth during the antibiotic chloramphenicol treatment. The proposed system can find applications in a broad field of biomedical diagnostics and therapy.
37

Wei, Shengli, Zhilei Song, Chongrong Wu, and Xiaonan Qu. "Study of dual closed-loop control strategy of exhaust gas recirculation for diesel engines." Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, no. 11 (November 20, 2018): 1380–90. http://dx.doi.org/10.1080/15567036.2018.1548516.

Full text
APA, Harvard, Vancouver, ISO, and other styles
38

Hardin, J. A., C. L. Jones, E. L. Bonjour, R. T. Noyes, R. L. Beeby, D. A. Eltiste, and S. Decker. "Ozone fumigation of stored grain; closed-loop recirculation and the rate of ozone consumption." Journal of Stored Products Research 46, no. 3 (July 2010): 149–54. http://dx.doi.org/10.1016/j.jspr.2010.03.002.

Full text
APA, Harvard, Vancouver, ISO, and other styles
39

Chen, S., and F. Yan. "Control of a dual-loop exhaust gas recirculation system for a turbocharged Diesel engine." International Journal of Automotive Technology 16, no. 5 (May 27, 2015): 733–38. http://dx.doi.org/10.1007/s12239-015-0074-6.

Full text
APA, Harvard, Vancouver, ISO, and other styles
40

Zhang, Junwen, Jianjun Yu, Nan Chi, Ze Dong, Xinying Li, Yufeng Shao, and Li Tao. "Multichannel optical frequency-locked multicarrier source generation based on multichannel recirculation frequency shifter loop." Optics Letters 37, no. 22 (November 12, 2012): 4714. http://dx.doi.org/10.1364/ol.37.004714.

Full text
APA, Harvard, Vancouver, ISO, and other styles
41

Gautier, Nicolas, and Jean-Luc Aider. "Upstream open loop control of the recirculation area downstream of a backward-facing step." Comptes Rendus Mécanique 342, no. 6-7 (June 2014): 382–88. http://dx.doi.org/10.1016/j.crme.2014.05.004.

Full text
APA, Harvard, Vancouver, ISO, and other styles
42

Rocha-Rios, José, Guillermo Quijano, Frédéric Thalasso, Sergio Revah, and Raul Muñoz. "Methane biodegradation in a two-phase partition internal loop airlift reactor with gas recirculation." Journal of Chemical Technology & Biotechnology 86, no. 3 (October 15, 2010): 353–60. http://dx.doi.org/10.1002/jctb.2523.

Full text
APA, Harvard, Vancouver, ISO, and other styles
43

NYERGES, Ádám, and Máté ZÖLDY. "Model development and experimental validation of an exhaust brake supported dual loop exhaust gas recirculation on a medium duty Diesel engine." Mechanics 26, no. 6 (December 7, 2020): 486–96. http://dx.doi.org/10.5755/j01.mech.26.6.25017.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Due to the new European emission norms internal combustion engines have to comply stricter rules. The new norms contain new requirements that were not included in previous regulations for example the decreased temperature of the cold start or the real driving emission part. The emission cycles for passenger vehicles are completely news, the stricter emission norms for commercial vehicles will follow them within a few years. Despite the increasing spread of alternative transmission systems in road transport Diesel engines are going to be remain in commercial vehicles in the next decades due to their good torque and fuel consumption performance. The emission of Diesel engines can be kept low by several way: by the modification of combustion processes, or by exhaust gas after treatment. To comply future regulations both of them seems to be necessary. By exhaust gas recirculation systems alternative Diesel combustion processes can be realized which can provide lower nitrogen-oxide emission and in several operation points also lower fuel consumption. Exhaust gas recirculation systems also can support the thermal management of a Diesel engine. To utilize the advantages of the recirculated exhaust gases a complex system is necessary to get a freedom in control possibilities: duel loop exhaust gas recirculated systems supplemented with supporter valves on the intake or on the exhaust side. In this paper a pressure and mass flow rate based control oriented engine model will be presented which contains high and low pressure exhaust gas recirculation systems and both of them are supported by exhaust brakes. The model considers four balance volumes and it has five state variables. The model is validated by an engine dyno measurements on a medium duty Diesel engine.
44

Cerrillo, Miriam, Laura Burgos, and August Bonmatí. "Biogas Upgrading and Ammonia Recovery from Livestock Manure Digestates in a Combined Electromethanogenic Biocathode—Hydrophobic Membrane System." Energies 14, no. 2 (January 19, 2021): 503. http://dx.doi.org/10.3390/en14020503.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Anaerobic digestion process can be improved in combination with bioelectrochemical systems in order to recover energy and resources from digestates. An electromethanogenic microbial electrolysis cell (MEC) coupled to an ammonia recovery system based on hydrophobic membranes (ARS-HM) has been developed in order to recover ammonia, reduce organic matter content and upgrade biogas from digested pig slurry. A lab-scale dual-chamber MEC was equipped with a cation exchange membrane (CEM) and ARS with a hydrophobic membrane in the catholyte recirculation loop, to promote ammonia migration and absorption in an acidic solution. On the other hand, an electromethanogenic biofilm was developed in the biocathode to promote the transformation of CO2 into methane. The average nitrogen transference through the CEM was of 0.36 gN m−2 h−1 with a removal efficiency of 31%, with the ARS-HM in the catholyte recirculation loop. The removal of ammonia from the cathode compartment helped to maintain a lower pH value for the electromethanogenic biomass (7.69 with the ARS-HM, against 8.88 without ARS-HM) and boosted methane production from 50 L m−3 d−1 to 73 L m−3 d−1. Results have shown that the integration of an electromethanogenic MEC with an ARS-HM allows for the concomitant recovery of energy and ammonia from high strength wastewater digestates.
45

Yang, Xiaoling, Zhefeng Wang, Ze Zhang, Shuangtao Chen, Yu Hou, and Liang Chen. "Thermodynamic Analysis of Air-Cycle Refrigeration Systems with Expansion Work Recovery for Compartment Air Conditioning." Applied Sciences 12, no. 10 (May 23, 2022): 5287. http://dx.doi.org/10.3390/app12105287.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
As a requirement for sustainable development, air-cycle refrigeration has received wide attention as a candidate for environmentally friendly air conditioning technology. In this study, the thermodynamic performance of air refrigeration cycles is investigated in compartment air conditioning. The effects of compressor efficiency, expander efficiency, ambient humidity, all-fresh-air supply and ambient pressure on the cycle performance are presented. The effects of compressor arrangement in the high-pressure cycle and the low-pressure cycle are compared. An open-loop high-pressure cycle has a larger COP than that of an open-loop low-pressure cycle but requires larger heat exchange. The performance of air refrigeration cycles with full fresh air is studied, and the influence of fresh air is discussed. Schemes for condensed water recirculation with wet compression are proposed, which can improve the COPs of open-loop low-pressure cycles by 44.7%, 48.8% and 48.4%. In the air conditioning of plateau trains, open-loop high-pressure cycles have slightly lower COPs, but they can supply air with elevated pressure and oxygen concentration.
46

Cho, Sung-Ho, Sung Hwan Hong, Jeong Whan Han, and Byung Don You. "Effect of Slag Layer on Flow Patterns in a Gas Stirred Ladle." Materials Science Forum 510-511 (March 2006): 490–93. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.490.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Flow patterns and mixing behaviors in a gas stirred steelmaking ladle with a slag layer were discussed using a water model experiment as well as a numerical simulation. While the water model experiment was performed to investigate the effect of slag on the mixing behavior in ladle, the numerical simulation was carried out to figure out the flow pattern in ladle with a slag layer. Slag viscosity and its thickness in ladle were considered as major variables. It was found that a slag layer made a great change in the flow pattern in ladle, which, in turn, affected on the mixing behavior in ladle. A flow pattern without a slag layer showed that rising bubbles eventually made a recirculation loop at the central area of the ladle and this flow pattern was regarded as a favorable flow pattern for the better mixing behavior. However, a flow pattern with a slag layer showed distorted and localized recirculating loop near side wall below slag layer. This eventually gave a longer mixing time in ladle with a slag layer. Moreover, as the gas flow rate increases, slag existing on top of the ladle was found to be entrained into the melt. Slag viscosity and its thickness were found to be major variables affecting the behavior of slag entrainment. Lower the slag viscosity and thicker the slag layer, much more slag on top of the melt was entrained into the melt.
47

Li, Ruicheng, Feng-Fei Jin, and Baoqiang Yan. "Boundary Output Feedback Stabilization for a Cascaded-Wave PDE-ODE System with Velocity Recirculation." Complexity 2021 (June 4, 2021): 1–15. http://dx.doi.org/10.1155/2021/9977714.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
This paper considers the output feedback stabilization for a cascaded-wave PDE-ODE system with velocity recirculation by boundary control. First, we choose a well-known exponentially stable system as its target system and find a backstepping transformation to design a state feedback controller for the original system. Second, we attempt to give an output feedback controller for the original system by introducing the observer. The resulting closed-loop system admits a unique solution which is proved to be exponentially stable. Finally, we give some numerical examples to prove the validity for the theoretical results.
48

Castel, C., D. Mazens, E. Favre, and M. Léonard. "Determination of diffusion coefficient from transitory uptake or release kinetics: Incidence of a recirculation loop." Chemical Engineering Science 63, no. 13 (July 2008): 3564–68. http://dx.doi.org/10.1016/j.ces.2008.03.016.

Full text
APA, Harvard, Vancouver, ISO, and other styles
49

Bao, Cheng, Kexun Zhang, Minggao Ouyang, Baolian Yi, and Pingwen Ming. "Dynamic Test and Real-time Control Platform of Anode Recirculation for PEM Fuel Cell Systems." Journal of Fuel Cell Science and Technology 3, no. 3 (February 21, 2006): 333–45. http://dx.doi.org/10.1115/1.2217956.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Anode recirculation is essential to the pure-hydrogen proton exchange membrane fuel cell system. Keeping the pressure difference between the anode and the cathode is also important to the membrane health. In this paper, a dynamic platform was designed for the recirculation test of injection pump and real-time control of the anode pressure tracking. The test bench can work in a wide range of conditions for high- and low-pressure application. Based on the MATLAB/xPC Target environment, some S functions were written to drive the PC board for the hardware-in-loop application. Then an analytical full-order and a reduced-order model were built with good accuracy. By linearization of the nonlinear dynamic model, a linear quadratic Gaussian algorithm based on state feedback was used for set-point tracking. Moreover, an adaptive fuzzy neural network with an on-line neural network identifier was also designed to improve the control robustness. The foundation of the test bench and realization of the real-time control algorithms are meaningful to the future application in fuel cell systems.
50

Srisuddee, Sura, Malinee Sriariyanun, Chanin Panjapornpon, and Atthasit Tawai. "Input/output Linearization Control Technique for Anaerobic Digestion Reactor with Recirculation." E3S Web of Conferences 141 (2020): 01007. http://dx.doi.org/10.1051/e3sconf/202014101007.

Full text
APA, Harvard, Vancouver, ISO, and other styles
Abstract:
Anaerobic digestion (AD) process has been generally applied in factories for wastewater treatment and energy recovery. For the AD processes, the continuously stirred tank reactor (CSTR) with recirculation are typically applied in industries for methane production from wastewater treatment. Since the recycle stream affects the inlet concentration of the reactor, the control performance of traditional PI and PID controllers used to manipulate control actuators may be limited. Additionally, the process control loops related to biochemical reactions are generally employed the operational experiences without process dynamic consideration. A control system based on input/output (I/O) linearization control technique for an anaerobic digestion (AD) process was developed in this work. The control system applied the concept of the I/O linearization technique, which followed dynamic behaviors of the reactor with a two-step (acidogenesis-methanogenesis) kinetic model. The volatile fatty acid (VFA) concentration was regulated by manipulation of the dilution rate to achieve the requested trajectories. Control performances of the closed-loop system were investigated by a simulation under servo and regulatory problems. The simulation results showed that the developed control scheme successfully forced the controlled output to achieve the desired set points and handled the introduced control problems.

To the bibliography