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Author

Ujjwal K. Saha

Bio: Ujjwal K. Saha is an academic researcher from Indian Institute of Technology Guwahati. The author has contributed to research in topics: Diesel engine & Diesel fuel. The author has an hindex of 28, co-authored 120 publications receiving 3565 citations. Previous affiliations of Ujjwal K. Saha include Indian Institute of Technology Bombay.


Papers
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Journal ArticleDOI
TL;DR: A series of experiments have been carried out in a developed liquid sloshing setup to estimate the pressure developed on the tank walls and the free surface displacement of water from the mean static level.

178 citations

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TL;DR: In this paper, a detailed review of various computational methods addressing the influence of various operating parameters and augmentation techniques has been reported from this review study, it is observed that with the selection of a proper computational methodology, the design, performance, and efficiency of a Savonius rotor can be enhanced significantly.
Abstract: In recent era, research and development activities in the field of renewable energy, especially wind and solar, have been considerably increased, due to the worldwide energy crisis and high global emission However, the available technical designs are not yet adequate to develop a reliable distributed wind energy converter for low wind speed conditions The Savonius rotor appears to be particularly promising for such conditions, but suffers from a low efficiency Till now, a number of experimentations have been carried out in the area of Savonius rotor to increase its efficiency These large-scale experimentations involve massive costs and hazards In this context, computational studies have shown a significant importance to carry out the research with large number of physical designs and parameters Over the past four decades, investigations have been carried out with various computational methodologies and turbulence models to optimize the different parameters and hence the efficiency of these rotors In the present paper, a detailed review of various computational methods addressing the influence of various operating parameters and augmentation techniques has been reported From this review study, it is observed that with the selection of a proper computational methodology, the design, performance, and efficiency of a Savonius rotor can be enhanced significantly

147 citations

Journal ArticleDOI
TL;DR: In this article, the effect of compression ratio on performance, combustion and emission characteristics of a rice bran biodiesel-biogas run dual fuel diesel engine was investigated, and experiments were conducted at three different compression ratios (CRs) of 18, 17.5 and 17, and at a fixed injection timing of 23° bottom top dead centre (BTDC) under different loading conditions.

145 citations

Journal ArticleDOI
TL;DR: In this article, the effect of syngas on the performance, combustion and emission characteristics of a diesel engine was studied at different loads, and three different volumetric compositions were examined in the diesel engine under dual fuel modes.

138 citations

Journal ArticleDOI
TL;DR: The most explored emulsified fuel in a diesel engine is the water in diesel emulsion as discussed by the authors, which is one of the most efficient and reliable energy conversion devices available till date.
Abstract: Diesel engine is one of the most efficient and reliable energy conversion devices available till date. During the beginning of twentieth century, the plenty of low cost diesel have engrossed people to run diesel engines with diesel. However, after more than a century, the scenario has just been reversed. The frantic use of diesel has now led to a situation where the global fossil diesel storage may last merely for a few decades. As a result, the price of diesel has reached to a momentous height. This is coupled with the serious environmental pollution created by its burning. These facts have stimulated researchers around the globe to search for suitable, sustainable, renewable, and cheap alternative to diesel fuel, which is environmentally benign too. Among many solutions proposed, emulsified fuel is one of them, which comes under the fuel modification techniques. In this method, two or more mutually immiscible fluids are mixed together, which is expected to run a diesel engine and replicate its performance, combustion and emission characteristics. The most explored emulsified fuel in a diesel engine is the water in diesel emulsion. Alongside, the emulsions prepared with animal fat, methanol, ethanol and few studies with emulsified biodiesels have also been reported. The present paper attempts to accumulate most of these studies under a single shed. Efforts have been made to analyze the numerous studies on emulsified fuel both qualitatively and quantitatively. The paper starts giving an introduction to the types of emulsion, their characteristics, and the criteria of preparing an effective emulsion, followed by the review of their performance, combustion, emission and spray characteristics when run in a diesel engine. At the end, some of the significant points have been addressed based on the extensive review on the state-of-the-art literature, followed by some possibilities of future research.

130 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the importance of urban physics related to the grand societal challenges is described, after which the spatial and temporal scales in urban physics and the associated model categories are outlined.

627 citations

Journal ArticleDOI
TL;DR: In this article, a dual-fuel engine with high-cetane fuel and natural gas injection is used to provide a source of ignition for the charge of a spark-ignition (SI) engine.

595 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide a perspective on the past, present and future of Computational Wind Engineering (CWE) and provide a more detailed view on CFD simulation of pedestrian-level wind conditions around buildings.

570 citations

01 Jan 2002
TL;DR: In this article, the aerodynamic design and performance of VAWTs based on the Darrieus concept is discussed, as well as future trends in design and the inherent socioeconomic and environmental friendly aspects of wind energy as an alternate source of energy.
Abstract: Wind energy is the fastest growing alternate source of energy in the world since its purely economic potential is complemented by its great positive environmental impact. The wind turbine, whether it may be a Horizontal-Axis Wind Turbine (HAWT) or a Vertical-Axis Wind Turbine (VAWT), offers a practical way to convert the wind energy into electrical or mechanical energy. Although this book focuses on the aerodynamic design and performance of VAWTs based on the Darrieus concept, it also discusses the comparison between HAWTs and VAWTs, future trends in design and the inherent socio-economic and environmental friendly aspects of wind energy as an alternate source of energy.

549 citations

Journal ArticleDOI
TL;DR: An attempt has been made to review the applications of fuzzy logic based models in renewable energy systems namely solar, wind, bio-energy, micro-grid and hybrid applications and indicates that fuzzy based models provide realistic estimates.
Abstract: In recent years, with the advent of globalization, the world is witnessing a steep rise in its energy consumption. The world is transforming itself into an industrial and knowledge society from an agricultural one which in turn makes the growth, energy intensive resulting in emissions. Energy modeling and energy planning is vital for the future economic prosperity and environmental security. Soft computing techniques such as fuzzy logic, neural networks, genetic algorithms are being adopted in energy modeling to precisely map the energy systems. In this paper, an attempt has been made to review the applications of fuzzy logic based models in renewable energy systems namely solar, wind, bio-energy, micro-grid and hybrid applications. It is found that fuzzy based models are extensively used in recent years for site assessment, for installing of photovoltaic/wind farms, power point tracking in solar photovoltaic/wind, optimization among conflicting criteria. The review indicates that fuzzy based models provide realistic estimates.

411 citations