The environmental pollution by trace heavy metals is a severe problem for the environment and human health. In this paper, the liquid jet of CsNO3 solution employed was introduced to the measurement chamber and detect...
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A new 1D model using the real gas property is proposed to predict ejector performance at critical and sub-critical operational modes, while most previous 1D models usually used the ideal gas property and only predicte...
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A new 1D model using the real gas property is proposed to predict ejector performance at critical and sub-critical operational modes, while most previous 1D models usually used the ideal gas property and only predicted ejector performance at critical mode operation. Constant pressure mixing is assumed to occur inside the constant area section of the ejector at critical and sub-critical mode operation, and the effectiveness of the model is verified against experimental data. The results show that the proposed model accurately predicts ejector performance over all ranges of operation. The 1D model is a useful tool for predicting ejector performance within larger refrigeration cycle models.
The application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas is reviewed in this *** include the combustion characteristics of direct injection engine fueled with hydrogen en...
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The application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas is reviewed in this *** include the combustion characteristics of direct injection engine fueled with hydrogen enriched natural gas,visualization study of direct injection combustion of hydrogen enriched natural gas using a constant volume vessel,and the fundamental study of turbulent premixed combustion of hydrogen enriched natural *** effect of additional hydrogen on the combustion process of natural gas engine is investigated from the fundamental view of the interaction between combustion reaction and turbulent flow.
Severe accident analysis is important for the safety evaluation of a nuclear power plant (NPP). In this paper, analysis has been performed for a Chinese three-loop Pressurized Water Reactor (PWR) severe accident induc...
Severe accident analysis is important for the safety evaluation of a nuclear power plant (NPP). In this paper, analysis has been performed for a Chinese three-loop Pressurized Water Reactor (PWR) severe accident induced by loss of coolant accident (LOCA) along with Station- Block-Out (SBO) using the MIDAC code. The simulation results show the influence of different break sizes in the cold leg on the severe accident progression. Important parameters, such as primary coolant system (RCS) pressure, core melting time, pressure vessel rupture time. are analyzed with three different break sizes in the cold leg. With the break size of 0.002 m 2 , the reactor core starts to melt at 1481 s and the lower head fails at 10,317 s after the accident occurs. With a larger break size of 0.05 m 2 , the reactor core starts to melt at 1066 s and the lower head fails at 2473 s. If the break size is further enlarged to 0.2 m 2 , the reactor core starts to melt at 422 s and the lower head fails at 1757 s. Another case in which a hot leg break is with the size of 0.002 m 2 is performed. The reactor core starts to melt at 3641 s and the lower head fails at 14,744 s. It is less severe than the cold leg break accident. The severe accident prevention and mitigation measures are summarized based on the computation results. The results are helpful to develop the management strategies and guideline for the severe accident of the similar types of PWRs.
This paper provides a comprehensive analysis on cooling tower fouling data taken from seven 15.54 mm I.D. helically ribbed, copper tubes and a plain tube at Re = 16000. There are two key processes during fouling forma...
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This paper provides a comprehensive analysis on cooling tower fouling data taken from seven 15.54 mm I.D. helically ribbed, copper tubes and a plain tube at Re = 16000. There are two key processes during fouling formation： fouling deposition and fouling removal, which can be determined by mass transfer and fluid friction respectively. The mass transfer coefficient can be calculated through three analogies： Prandtl analogy, VonKarman analogy, and Chilton-Colburn analogy. Based on our analyses, Von-Karman analogy is the optimized analogy, which can well predict the formation of cooling tower fouling. Series of semi-theoretical fouling correlations as a function of the product of area indexes and efficiency indexes were developed, which can be applicable to different internally ribbed geometries. The correlations can be directly used to assess the fouling ootential of enhanced tubes in actual coolinu tower water situations.
Generally, the Offset Strip Fin (OSF) in a plate-fin heat exchanger provides a greater heat transfer coefficient than plain plate-fin, but it also leads to an increase in flow friction. A new parameter, called relativ...
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Generally, the Offset Strip Fin (OSF) in a plate-fin heat exchanger provides a greater heat transfer coefficient than plain plate-fin, but it also leads to an increase in flow friction. A new parameter, called relative entropy generation distribution factor, Ψ * , is proposed to evaluate the thermodynamic advantages of OSFs. This parameter presents a ratio of relative changes of entropy generation. The relative effects of the geometrical parameters α, γ and δ are discussed. The results show that there exist the optimum values of α and γ at a certain flow condition, which obviously maximize the degree of the heat transfer enhancement of OSFs.
Solar receiver reactor is the key component of supercritical water gasification of biomass using concentrating solar energy, and itsthermal performance directly affects the thermal efficiency and biomass gasification ...
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Solar receiver reactor is the key component of supercritical water gasification of biomass using concentrating solar energy, and itsthermal performance directly affects the thermal efficiency and biomass gasification results. The temperature distributions of solar receiver reactor and reactant fluid are *** results showed that direct normal solar irradiation (DNI) have prominent effect on the temperature of cavity type solar receiver reactor, thus affecting the SCWG reaction behaviors and gasification results. A series of on-sun experiments were carried out,temperature is relatively stable withDNI small fluctuations, and the nominal fluid temperatures at the outlet of reactor varied in the range 500–650 o C, which could completely meet the need of the temperature for biomass gasification in supercritical *** compounds of biomass (ethylene glycol, ethanol,glycerin and glucose) were continuously gasified under SCW conditions to generate hydrogen-rich fuel gas in the apparatus. Gas yields, carbon gasification efficiency and the total gasification efficiency increase with increasing DNI. The range of GE and CE is 48.5-105.8%, 37.5-95.6%, *** thermal performance and gasification results show thatsolar receiver/reactor used in this study is one of the good configurations that can be used for SCWG of biomass using concentrating solar energy.
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