Study on the Numerical Model of Transonic Wind Tunnel Test Section

The authors consider numerical simulations of transonic flows through various turbine cascades in a confined channel which approximates boundaries of real wind tunnel.The boundaries of the wind tunnel are impermeable or there can be permeable tailboards to diminish shock wave reflections.The mathematical model is based on Favre-averaged Navier-Stokes equations closed by a turbulence model and model of transition to turbulence.The mathematical model is solved by an implicit finite volume method with multi-block grids.Several types of turbine blade cascades with subsonic or supersonic inlet are presented.The results are compared with optical measurements and simulations of periodic cascades.The validity of experimental reference flow parameters in relation to computed flow patterns is discussed.     

Influence of Technological Processes on Biologically Active Compounds of Produced Grapes Juices

Grape juice quality can be substantially influenced by different processing methods and their parameters. This study deals with the influence of thermomaceration temperature and its holding time on important juice quality parameters such as the content of trans-resveratrol, trans-piceid, trans-ε-viniferin, and 2,4,6-trihydroxyphenantrene-2-O-glucoside. All the aforementioned compounds together with antioxidative capacity, total polyphenols, and antimutagenic activity were measured. This study used the following grapes: Blaufränkisch, Blaufränkisch bio, Saint Laurent, Grüner Veltliner, Grüner Veltliner bio, and Müller-Thurgau. For all tested grape varieties, the most important processing parameters were temperature and thermomaceration holding time. There were no significant differences in the content of the studied compounds. Three preservation technologies, freezing, bottle pasteurization, and high-pressure treatment, were also studied regarding the content of abovementioned biologically active compounds. Results of this study can be immediately applied to grape juice production.     

Heat Integration retrofit analysis—an oil refinery case study by Retrofit Tracing Grid Diagram

Heat Integration has been established over the last decades as a proven chemical engineering methodology. Two design implementations are often used in the industry: grassroots and retrofit. Although various methods have been developed for retrofit, it still needs more development to ensure simultaneously thermodynamic feasibility and economic viability. In this paper, a novel graphical approach has been developed to facilitate the understanding of the current situation and scope of improvement. The Retrofit Tracing Grid Diagram presents all streams and heat exchangers in temperature scale and the heat exchangers are clearly separated from each other, enabling clear visualisation of the current state. The tool incorporates the previously developed Cross-Pinch Analysis as well as path approach for retrofit. Additionally, the non-vertical heat transfer can be evaluated. The application of the developed tool has been validated on an oil refinery case study. The applicability of the tool is evident as it can reveal additional options for modification that none of the previous methods considered.     

Cleaner production,Process Integration and intensification

A considerable number of studies have been performed and are ongoing for enhancing cleaner production, process integration and also process intensification. These topics reflect some of the most important challenges of our society and have been targeted in this journal. Considerable research effort has been devoted to addressing process integration and process intensification as well as environmentally friendlier production. This article has made an attempt to provide a short assessment of the current state-of-art covered in the recent publications.     

Efficiency of microbial inoculation for a cleaner composting technology

Clean Technologies and Environmental Policy - There are contrasting opinions on the utilisation of microbial inoculant (MI) as a bioremediation technology for composting. The effectiveness can be...     

Influence of fatty acids in waste cooking oil for cleaner biodiesel

Physiochemical properties of biodiesel, a sustainable and green alternative fuel produced from renewable resources, are greatly influenced by the structural features of polyunsaturated, monounsaturated and saturated fatty acids. Two feedstock oils, potentially contribution to cleaner technologies, refined cooking oil and waste cooking oil derived from palm olein have been studied. Fatty acid compositions of the refined cooking oil and waste cooking oil were analysed and confronted with other literature sources. Critical parameters such as cetane number (CN), iodine value, cold filter plugging point (CFPP) and oxidation stability (OS) were correlated with long-chain saturated factor and degree of unsaturation (DU) of fatty acid to match the international standards of cleaner biodiesel. OS in biodiesel has been met with the absence of linolenic acid. High saturated fatty acid provides high CN. The iodine value of feedstock oil met the European standard where the DU of the oils was less than 138. However, CFPP of refined cooking oil and waste cooking oil did not meet the demanding Spanish regional (RD 61/2006) standard due to the presence of stearic and palmitic acid, which tended to clog the fuel filter by precipitating while the biodiesel becomes cool. With the proposed triangular chart for biodiesel properties prediction, potential biodiesel fuels from various feedstock oils can be analysed.