scholarly journals Improving Centrifugal Compressor Performance by Optimizing the Design of Impellers Using Genetic Algorithm and Computational Fluid Dynamics Methods

2019 ◽  
Vol 11 (19) ◽  
pp. 5409 ◽  
Author(s):  
Mohammad Omidi ◽  
Shu-Jie Liu ◽  
Soheil Mohtaram ◽  
Hui-Tian Lu ◽  
Hong-Chao Zhang

It has always been important to study the development and improvement of the design of turbomachines, owing to the numerous uses of turbomachines and their high energy consumption. Accordingly, optimizing turbomachine performance is crucial for sustainable development. The design of impellers significantly affects the performance of centrifugal compressors. Numerous models and design methods proposed for this subject area, however, old and based on the 1D scheme. The present article developed a hybrid optimization model based on genetic algorithms (GA) and a 3D simulation of compressors to examine the certain parameters such as blade angle at leading and trailing edges and the starting point of splitter blades. New impeller design is proposed to optimize the base compressor. The contribution of this paper includes the automatic creation of generations for achieving the optimal design and designing splitter blades using a novel method. The present study concludes with presenting a new, more efficient, and stable design.

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 845
Author(s):  
Sonia Bonacci ◽  
Giuseppe Iriti ◽  
Stefano Mancuso ◽  
Paolo Novelli ◽  
Rosina Paonessa ◽  
...  

The use of toxic solvents, high energy consumption, the production of waste and the application of traditional processes that do not follow the principles of green chemistry are problems for the pharmaceutical industry. The organic synthesis of chemical structures that represent the starting point for obtaining active pharmacological compounds, such as benzimidazole derivatives, has become a focal point in chemistry. Benzimidazole derivatives have found very strong applications in medicine. Their synthesis is often based on methods that are not convenient and not very respectful of the environment. A simple montmorillonite K10 (MK10) catalyzed method for the synthesis of benzimidazole derivatives has been developed. The use of MK10 for heterogeneous catalysis provides various advantages: the reaction yields are decidedly high, the work-up procedures of the reaction are easy and suitable, there is an increase in selectivity and the possibility of recycling the catalyst without waste formation is demonstrated. The reactions were carried out in solvent-free conditions and in a short reaction time using inexpensive and environmentally friendly heterogeneous catalysis. It has been shown that the reaction process is applicable in the industrial field.


2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Roberto Contino ◽  
Kevin Max ◽  
Rashmish K. Mishra

Abstract We consider the possible existence of a SM-neutral and light dark sector coupled to the visible sector through irrelevant portal interactions. Scenarios of this kind are motivated by dark matter and arise in various extensions of the Standard Model. We characterize the dark dynamics in terms of one ultraviolet scale Λuv, at which the exchange of heavy mediator fields generates the portal operators, and by one infrared scale ΛIR, setting the mass gap. At energies ΛIR « E « Λuv the dark sector behaves like a conformal field theory and its phenomenology can be studied model independently. We derive the constraints set on this scenario by high- and low-energy laboratory experiments and by astrophysical observations. Our results are conservative and serve as a minimum requirement that must be fulfilled by the broad class of models satisfying our assumptions, of which we give several examples. The experimental constraints are derived in a manner consistent with the validity of the effective field theory used to define the portal interactions. We find that high-energy colliders give the strongest bounds and exclude UV scales up to a few TeV, but only in specific ranges of the IR scale. The picture emerging from current searches can be taken as a starting point to design a future experimental strategy with broader sensitivity.


Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 76
Author(s):  
Luciano Nicastro ◽  
Cristiano Guidorzi ◽  
Eliana Palazzi ◽  
Luca Zampieri ◽  
Massimo Turatto ◽  
...  

The origin and phenomenology of the Fast Radio Burst (FRB) remains unknown despite more than a decade of efforts. Though several models have been proposed to explain the observed data, none is able to explain alone the variety of events so far recorded. The leading models consider magnetars as potential FRB sources. The recent detection of FRBs from the galactic magnetar SGR J1935+2154 seems to support them. Still, emission duration and energetic budget challenge all these models. Like for other classes of objects initially detected in a single band, it appeared clear that any solution to the FRB enigma could only come from a coordinated observational and theoretical effort in an as wide as possible energy band. In particular, the detection and localisation of optical/NIR or/and high-energy counterparts seemed an unavoidable starting point that could shed light on the FRB physics. Multiwavelength (MWL) search campaigns were conducted for several FRBs, in particular for repeaters. Here we summarize the observational and theoretical results and the perspectives in view of the several new sources accurately localised that will likely be identified by various radio facilities worldwide. We conclude that more dedicated MWL campaigns sensitive to the millisecond–minute timescale transients are needed to address the various aspects involved in the identification of FRB counterparts. Dedicated instrumentation could be one of the key points in this respect. In the optical/NIR band, fast photometry looks to be the only viable strategy. Additionally, small/medium size radiotelescopes co-pointing higher energies telescopes look a very interesting and cheap complementary observational strategy.


1993 ◽  
Vol 28 (7) ◽  
pp. 243-250 ◽  
Author(s):  
Y. Suzuki ◽  
S. Miyahara ◽  
K. Takeishi

Gas-permeable film can separate air and water, and at the same time, let oxygen diffuse from the air to the water through the film. An oxygen supply method using this film was investigated for the purpose of reducing energy consumption for wastewater treatment. The oxygen transfer rate was measured for the cases with or without biofilm, which proved the high rate of oxygen transfer in the case with nitrifying biofilm which performed nitrification. When the Gas-permeable film with nitrifying biofilm was applied to the treatment of wastewater, denitrifying biofilm formed on the nitrifying biofilm, and simultaneous nitrification and denitrification occurred, resulting in the high rate of organic matter and T-N removal (7 gTOC/m2/d and 4 gT-N/m2/d, respectively). However, periodic sloughing of the denitrifying biofilm was needed to keep the oxygen transfer rate high. Energy consumption of the process using the film in the form of tubes was estimated to be less than 40% of that of the activated sludge process.


2013 ◽  
Vol 687 ◽  
pp. 255-261 ◽  
Author(s):  
Sandra Cunha ◽  
José Barroso Aguiar ◽  
Victor Ferreira ◽  
António Tadeu

Increasingly in a society with a high growth rate and standards of comfort, the need to minimize the currently high energy consumption by taking advantage of renewable energy sources arises. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing for an increase in the level of thermal comfort and reduction of the use of heating, ventilation and air conditioning (HVAC) equipment, using only the energy supplied by the sun. However, the incorporation of PCM in mortars modifies some of its characteristics. Therefore, the main objective of this study was the characterization of mortars doped with two different phase change materials. Specific properties of different PCM, such as particle size, shape and enthalpy were studied, as well as the properties of the fresh and hardened state of these mortars. Nine different compositions were developed which were initially doped with microcapsules of PCM A and subsequently doped with microcapsules of PCM B. It was possible to observe that the incorporation of phase change materials in mortars causes differences in properties such as compressive strength, flexural strength and shrinkage. After the study of the behaviour of these mortars with the incorporation of two different phase change materials, it was possible to select the composition with a better compromise between its aesthetic appearance, physical and mechanical characteristics.


2013 ◽  
Vol 423-426 ◽  
pp. 667-673 ◽  
Author(s):  
Fan Wen Xin ◽  
Zhi Qiang Xu ◽  
Ya Nan Tu ◽  
Wei Yang ◽  
Xiang Yu Han ◽  
...  

For solving the problems of high energy consumption and high capacity of water-absorption, microwave dehydration technology of lignite was studied in this paper. A self-developed microwave system was used for the experiment on dehydration of lignite from eastern Inner Mongolia. It was proved that the condition of moisture migration was improved and microwave dehydration had a unique mechanism. By analyzing the effects of microwave powers, coal particle sizes, and lignite qualities on drying characteristics, it was found that the moisture decreased when the microwave power increased. it was found that the higher the power was, the faster the moisture decreased; the smaller the particle size was, the faster the moisture decreased; the less the lignite was, the faster the moisture decreased. Through the scanning electron microscope analysis, it was concluded that microwave had no significant effect on the smooth particles, and the fibrous particles and clusters particles tended to be smooth under the effect of microwave. Therefore, the interface of lignite was relatively stable, and not easy to reabsorb water after microwave.


2014 ◽  
Vol 4 (1) ◽  
pp. 1-8
Author(s):  
Tanvi Gautam

Subject area Leadership, human resource management, crisis management, change management and communication. Study level/applicability Executive education; postgraduate; undergraduate. Case overview This case study describes the collapse of Satyam, a leading IT industry service provider from India. Satyam went into a crisis mode after revelation of financial fraud by its Chairman. This resulted in a crisis not just for the company, its clients and employees – but it also had the potential to shake up the entire Indian IT industry the world over, by shattering investor and client confidence in the Indian IT sector. The case provides the students with an inside view of the unfolding of events at Satyam and the people challenges that emerge in a crisis scenario. The case outlines reactions from the industry, government, clients and employees as they tried to make sense of a very chaotic situation, and its multi-level ramifications both within India and outside. The case ends with Thallapalli Hari, the Global Head of Marketing and Communication and ex-head of HR, trying to visualise and prioritise a course of action to propose to other members of the leadership team. Expected learning outcomes The key aim of this case is to provide a backdrop to the crisis, and also help students put themselves in the role of an HR crisis manager as well as portray the decision making and communication challenges that emerge in chaotic situations. The importance of an immediate and yet strategic response is emphasised and the case is a great starting point to have a discussion on the competencies and skills required in HR to lead under unusual circumstances. This case allows participants to get an in-depth understanding of the collapse of Satyam. The case also illustrates principles of leadership, change management and communication, in particular: Leadership: The Satyam story is an HR and leadership crisis nightmare come true. What should an HR leader do when you wake up to find your company with a ruined reputation, minimal financial capital, 53,000 employees on the payroll and more than 500 clients with pending deliverables worldwide. Where do you begin? The case illustrates a situation where immediate action is required to stop the tailspin into which the company was heading. Change management: The situation demanded that change be managed from a chaotic system to a stable system. The big issue though remains as to how one can get a system into a state of stability when everything is changing at the same time. Most change management plans have some stable variables, however in the case of Satyam there were multiple changes taking place simultaneously. A combination of change in leadership, client relationships, employee trust and confidence, market reactions together make for a perfect storm. Dealing with even one of these changes is a challenge for a company. In the case of Satyam, its entire existence was at stake. Communication: The demands for communicating effectively in a crisis situation are different than communicating under stable systems. The choice of medium, the speed of response, the content all need careful monitoring. Whereas most companies have teams that separately deal with internal and external communication, Satyam provides a unique situation where managing both effectively at the same time was critical to the future of the firm. The stakes for effective communication are much higher under the circumstances. This case can be used in organizational behaviour, human resources and corporate communications modules being taught to under-graduates, post-graduates and for executive education. Supplementary materials Teaching notes are available for educators only. Please contact your library to gain login details or email [email protected] to request teaching notes.


2014 ◽  
Vol 912-914 ◽  
pp. 483-485
Author(s):  
Chen Rong ◽  
David Chan

This paper introduce the basic characteristics of LIFEHOPE Military Fire Blanket, as for independent intellectual property rights new material, we use it is heat insulation, heat preservation to save energy for glass furnace etc. Meanwhile we will explain and put forward the meaning of application of LIFEHOPE military fire Blanket for high energy consumption and heavy pollution industry and enterprise.


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