Numerical Study on the Characteristics of Methane Hedging Combustion in a Heat Cycle Porous Media Burner

With the rapid development of portable devices and micro-small sensors, the demand for small-scale power supplies and high-energy-density energy supply systems is increasing. Comparing with the current popular lithium batteries, micro-scale burners based on micro-thermal photoelectric systems have features of high power density and high energy density, the micro-scale burner is the most critical part of the micro-thermal photovoltaic system. In this paper, the combustor was designed as a heat cycle structure and filled with porous media to improve the combustion characteristics of the micro combustor. In addition, the influence of the porous media distribution on the burner center temperature and wall temperature distribution were studied through numerical simulation. Furthermore, the temperature distribution of the combustor was studied by changing the porous media parameters and the wall parameters. The research results show that the heat cycle structure can reduce heat loss and improve combustion efficiency. When the combustion chamber is filled with porous media, it makes the radial center temperature rise by about 50 K and the temperature distribution more uniform. When filling the heat cycle channel with porous media the wall temperature can be increased. Finally, the study also found that as methane is combusted in the combustor, the temperature of the outer wall gradually increases as the intake air velocity increases. The results of this study provide a theoretical and practical basis for the further design of high-efficiency combustion micro-scale burners in the future.

Estimation of the efficiency of the thermal cycle of a piston internal combustion engine

Authors Rusinov R.V., Hoodorozhkov S.I., Dobretsov R.Yu., [email protected]. Estimation of the efficiency of the thermal cycle of a piston internal combustion engine The article proposes a simplified technique for the operational assessment of the efficiency of the heat cycle of a piston internal combustion engine. A feature of the developed computational model is the release of the amount of heat consumed for the production of only mechanical energy in the form of a separate component of the heat balance of the cycle. The value of this component is determined by calculation (or according to the results of experiments) in advance, which makes it possible to reduce the number of pre(determined initial data. The methodology is based on a mathematical description of thermodynamic processes occurring during the development of the thermal cycle of an engine with ignition of the working mixture from compression (diesel engine), which allows it to be expanded to new engines of design, including those operating under electronic control. The objects for the application of the calculation method can be diesel engines installed on transport vehicles, both individually and as part of a hybrid power plant, as well as engines of stationary or transportable power plants. The very principle underlying the model can be implemented for engines of other purposes and other thermal cycles. Keywords: heat cycle; the working process; diesel; heat content of the working fluid; expansion

An innovative designed machine or chamber build by multimodal approaches for COVID-19(SARS-CoV2) inactivation for household, office and hospital purpose

Inactivation of SARS- CoV 2 from different items like vegetables, fruits, parcels, coins, masks, personal protection equipment, etc used in domestic, office and hospital purposes is now very essential work to break transmission of this pandemic virus. Washing of the purchased materials from markets, our hands and washing of other items by water or soap water have increased many folds. For this purpose, an innovative machine (2ft length, 1.5ft breadth and 1.5 ft height) has been designed by multimodal approaches. The approaches includes UVC (254 nm), heat and copper metal treatment for inactivation of SARS CoV2. Machine includes two cycles, one UVC cycle and another heat cycle to inactivate or kill virus. Both cycles can be operated at one time or separately one after another. In this machine four UVC tubes (each 15 W) were fitted in different angles to irradiate maximum UVC to the items distantly located in the cabinet of machine. The dose of UVC, time of the exposure and maximum distance of the item were standardized in such as way that 99.999% inactivation of SARS- CoV2 occurred within 30 to 40 min The maximum dose was 18,331 J/m2 of UVC in this cabinet. SARS CoV2 isolate multiplied in Vero-E6 cell line and treated by UVC cycle at the maximum distance 9 inch and heat cycle at 50 to 600C temperature separately for 30 to 40 min. Infectivity of treated virus was tested in Vero E6 cell line by TCID 50 assay and this assay has confirmed that this treated virus has no infection capacity. In conclusion, this designed cabinet must serve our society as proper decontamination or SARS CoV2 inactivation in pandemic situation to break the transmission chain of this virus and save our precious water.

Collapse Resistance Under Combined External Pressure and Bending Deformation of Coated Linepipe

As offshore pipeline projects have expanded to deeper water regions with depths of more than 2 000 m, higher resistance against collapse by external pressure is now required in linepipe. Collapse resistance is mainly controlled by the pipe geometry and compressive yield strength. In UOE pipe, the compressive yield strength along the circumferential direction changes dramatically due to tensile pre-strain that occurs in pipe forming processes such as the expansion process. In order to improve the compressive yield strength of pipes, it is important to consider the Bauschinger effect caused by pipe expansion. As the mechanism of this effect, it is understood that internal stress is generated by the accumulation of dislocations, and this reduces reverse flow stress. Compressive yield strength is also changed by the thermal cycle associated with application of fusion-bond epoxy in pipe anti-corrosion coating by induction heating. In the typical thermal heat cycle of this coating process, the maximum heating temperature is from 200 °C to 250 °C. In this case, compressive yield strength increases as an effect of the thermal cycle, resulting in increased collapse resistance. Thus, for deep water application of UEO linepipe, it is important to clarify the conflicting effects of the Bauschinger effect and the thermal heat cycle on compressive yield strength. During installation of deep water pipelines by a method such as J-lay, curvature is imposed on the pipe axis, but the circumferential bending that leads to ovalization is determined by the interaction of the curvature of bending deformation. This bending deformation decreases collapse resistance. The interaction of external pressure and bending is also important when evaluating collapse. Against this background, this study discusses the collapse criteria for coated linepipe and their bending interaction against collapse based on a full-scale collapse test under external pressure with and without bending loading. The effect of the thermal heat cycle on linepipe collapse criteria is also discussed based on the results of tensile pre-strain tests with simulation of the thermal cycle and a collapse calculation by FEA.