Wyniki wyszukiwania - BazTech

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Efficiency Analysis of the Generation of Energy in a Biogas CHP System and its Management in a Waste Landfill – Case Study

Ciuła Józef, Generowicz Agnieszka, Gaska Krzysztof, Gronba-Chyła Anna

Journal of Ecological Engineering

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2022

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Vol. 23, nr 7

143--156

EN

As a waste neutralization facility, the landfill is a kind of bioreactor producing landfill gas or (LFG) - biogas, which should be captured and neutralised for environmental reasons. One of the ways of its utilisation is the combined production of heat and electrical energy in combined heat and power (CHP) cogeneration systems. For that purpose, the assessment of the energy efficiency of a cogeneration unit was undertaken in this work on the basis of the unit performance over the last 5 years. The analysis of the CHP system energy performance demonstrated that the ratios range at the lower limits for units up to 0.5 MW. The lower efficiency of fuel chemical conversion in the CHP plant (0.70) stems from the failure to use the rated thermal and electrical power fully (74.2%), which is caused by the insufficient stream of biogas collected from the landfill (161.46 m3∙h-1). The analysis of the generated energy usage, particularly in terms of heat, has shown a surplus which is not used and therefore is a loss. The proposed solutions in this area should optimize the use of heat generated from the renewable source, i.e. landfill biogas.

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Reflection-refraction coefficients and energy ratios in couple stress micropolar thermoviscous elastic solid

Sahrawat Ravinder Kumar, Poonam

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 2

47--69

EN

The reflection and refraction phenomenon of propagation of waves in couple stress micropolar thermoviscous elastic solid media with independent viscoelastic and micropolar properties have been studied. The structure of the model has been taken such that the plane interface is divides the given media into two half spaces in perfect contact. Here, we find that there are five waves, one of them is propagating independently while others are set of two coupled waves travelling with different speeds. Energy ratios, reflection and refraction coefficients relative to numerous reflected and refracted waves have been investigated when set of two coupled longitudinal waves and set of two coupled transverse waves strike at the interface through the solid medium. The inequality of energy ratios, refraction coefficients and reflection coefficients are evaluated numerically and presented graphically under three theories of thermoelasticity, namely, Green-Lindsay theory (GL), Lord-Shulman theory (LS), Coupled theory (CT) versus angular frequency and angle of incidence.

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New gas-liquid two-phase flow pattern maps based on the energy ratio of pressure fluctuation through a Venturi tube

Sun Zhiqiang, Chen Luyang, Yao Fengyan

Metrology and Measurement Systems

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2019

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Vol. 26, nr 2

241--252

EN

To find effective and practical methods to distinguish gas-liquid two-phase flow patterns, new flow pattern maps are established using the differential pressure through a classical Venturi tube. The differential pressure signal was first decomposed adaptively into a series of intrinsic mode functions (IMFs) by the ensemble empirical mode decomposition. Hilbert marginal spectra of the IMFs showed that the flow patterns are related to the amplitude of the pressure fluctuation. The cross-correlation method was employed to sift the characteristic IMF, and then the energy ratio of the characteristic IMF to the raw signal was proposed to construct flow pattern maps with the volumetric void fraction and with the two-phase Reynolds number, respectively. The identification rates of these two maps are verified to be 91.18% and 92.65%. This approach provides a cost-effective solution to the difficult problem of identifying gas-liquid flow patterns in the industrial field.