scholarly journals A Brief Theoretical Analysis on the Ventilation Characteristics of the Multi-Intake-Well Air Supply System in a Spillway Tunnel

2019 ◽  
Vol 9 (14) ◽  
pp. 2793
Author(s):  
Jijian Lian ◽  
Panhong Ren ◽  
Chunfeng Qi ◽  
Fang Liu ◽  
Qunan Ouyang
Keyword(s):  
Drag Coefficient ◽  
Theoretical Approach ◽  
Supply System ◽  
Structural Factors ◽  
Air Supply ◽  
Air Intake ◽  
Spillway Tunnel ◽  
High Dams ◽  
Supply Systems ◽  
Theoretical Results

It is of great significance to study the ventilation characteristics of air supply systems in spillway tunnels, especially for high dams. In this paper, a brief theoretical approach to evaluate the ventilation characteristics of a multi-intake-well air supply system was established, which was mainly derived from the Bernoulli equation and continuity equation. With this approach, an analysis of the ventilation characteristics of the Jinping-I project spillway tunnel was carried out. A comparison of the theoretical results and prototype data suggested the theoretical approach to be valid and practical. The value of the drag coefficient at the air-water interface should be calibrated before evaluation because the drag coefficient is crucial for the accuracy of theoretical results. In addition, the influences of certain structural factors of the spillway tunnel and air intake well on the ventilation characteristics of multi-intake-well air supply systems are investigated.

Influence of Rain Protection Louver on the Noise Generated by Ship Engine Room Air Intake

2008 ◽  
Author(s):  
Manoj Kumar ◽  
S. L. Nikam
Keyword(s):  
Flow Field ◽  
Parametric Study ◽  
Noise Level ◽  
Supply System ◽  
Current Work ◽  
Significant Source ◽  
Angular Orientation ◽  
Engine Room ◽  
Air Supply ◽  
Air Intake

The air supply system, of a ship engine room, is a tremendous source of noise. Apart from the noise from air-intake fan, the rain protection louver, which guides the airflow and protects the fan and the duct from rain, is also a significant source of noise. The influence of the air-intake louver, on the noise generated by the engine room air-intake, has been studied by numerically simulating the flow field as well as on the basis of on-board measurements and simple experiments. In order to analyze the noise generated by the louver, a parametric study has been carried out based on two variables, the angular orientation of the slats of the louver and the spacing between the slats. The study shows that the noise level reduces significantly by changing the angular orientation of the slats, making them inline with the flow. It is also observed that, by increasing the spacing between the slats, the noise level can be reduced. The current work is a part of a study to develop guidelines to limit noise level, due to engine room air intake, on-board a ship.

scholarly journals Model Based Biomass System Design of Feedstock Supply Systems for Bioenergy Production

2013 ◽  
Author(s):  
Kara G. Cafferty ◽  
David J. Muth ◽  
Jacob J. Jacobson ◽  
Kenneth M. Bryden
Keyword(s):  
Supply Chain ◽  
Corn Stover ◽  
Cellulosic Ethanol ◽  
Supply System ◽  
Cellulosic Biomass ◽  
Systems Dynamics ◽  
Climate Conditions ◽  
Unit Operations ◽  
Supply Systems

Engineering feedstock supply systems that deliver affordable, high-quality biomass remains a challenge for the emerging bioenergy industry. Cellulosic biomass is geographically distributed and has diverse physical and chemical properties. Because of this feedstock supply systems that deliver cellulosic biomass resources to biorefineries require integration of a broad set of engineered unit operations. These unit operations include harvest and collection, storage, preprocessing, and transportation processes. Design decisions for each feedstock supply system unit operation impact the engineering design and performance of the other system elements. These interdependencies are further complicated by spatial and temporal variances such as climate conditions and biomass characteristics. This paper develops an integrated model that couples a SQL-based data management engine and systems dynamics models to design and evaluate biomass feedstock supply systems. The integrated model, called the Biomass Logistics Model (BLM), includes a suite of databases that provide 1) engineering performance data for hundreds of equipment systems, 2) spatially explicit labor cost datasets, and 3) local tax and regulation data. The BLM analytic engine is built in the systems dynamics software package Powersim™. The BLM is designed to work with thermochemical and biochemical based biofuel conversion platforms and accommodates a range of cellulosic biomass types (i.e., herbaceous residues, short-rotation woody and herbaceous energy crops, woody residues, algae, etc.). The BLM simulates the flow of biomass through the entire supply chain, tracking changes in feedstock characteristics (i.e., moisture content, dry matter, ash content, and dry bulk density) as influenced by the various operations in the supply chain. By accounting for all of the equipment that comes into contact with biomass from the point of harvest to the throat of the conversion facility and the change in characteristics, the BLM evaluates economic performance of the engineered system, as well as determining energy consumption and green house gas performance of the design. This paper presents a BLM case study delivering corn stover to produce cellulosic ethanol. The case study utilizes the BLM to model the performance of several feedstock supply system designs. The case study also explores the impact of temporal variations in climate conditions to test the sensitivity of the engineering designs. Results from the case study show that under certain conditions corn stover can be delivered to the cellulosic ethanol biorefinery for $35/dry ton.

The Attention Economy and Esports: An Econometric Analysis of Twitch Viewership

2021 ◽  
pp. 1-14
Author(s):  
Nicholas M. Watanabe ◽  
Hanhan Xue ◽  
Joshua I. Newman ◽  
Grace Yan
Keyword(s):  
Theoretical Approach ◽  
Econometric Analysis ◽  
Scarce Resource ◽  
Structural Factors ◽  
Sport Organizations ◽  
Economic Framework ◽  
Attention Economy ◽  
Growing Body ◽  
And Behaviors ◽  
Using Data

With the expansion of the esports industry, there is a growing body of literature examining the motivations and behaviors of consumers and participants. The current study advances this line of research by considering esports consumption through an economic framework, which has been underutilized in this context. Specifically, the “attention economy” is introduced as a theoretical approach—which operates with the understanding that due to increased connectivity and availability of information, it is the attention of consumers that becomes a scarce resource for which organizations must compete. Using data from the Twitch streaming platform, the results of econometric analysis further highlight the importance of structural factors in drawing attention from online viewers. As such, this research advances the theoretical and empirical understanding of online viewership behaviors, while also providing important ramifications for both esports and traditional sport organizations attempting to capture the attention of users in the digital realm.

Thermal and mechanical improvement of the air supply system of a turbocharged piston engine

2021 ◽  
Vol 14 (2) ◽  
pp. 108-114
Author(s):  
Y. M. Brodov ◽  
L. V. Plotnikov ◽  
K. O. Desyatov
Keyword(s):  
Heat Transfer ◽  
Experimental Studies ◽  
Local Heat Transfer ◽  
Supply System ◽  
Scale Model ◽  
Piston Engine ◽  
Intake System ◽  
Gas Dynamic ◽  
Air Supply ◽  
Air Flows

A method of thermomechanical improvement of pulsating air flows in the intake system of a turbocharged piston engine is described. The main objective of this study is to develop a method for suppressing the rate of heat transfer to improve the reliability of a piston turbocharged engine. A brief review of the literature on improving the reliability of piston engines is given. Scientific and technical results were obtained on the basis of experimental studies on a full-scale model of a piston engine. The hot-wire anemometer method was used to obtain gas-dynamic and heatexchange characteristics of gas flows. Laboratory stands and instrumentation facilities are described in the article. The data on gas dynamics and heat exchange of stationary and pulsating air flows in gas-dynamic systems of various configurations as applied to the air supply system of a turbocharged piston engine are presented. A method of thermomechanical improvement of flows in the intake system of an engine based on a honeycomb is proposed in order to stabilize the pulsating flow and suppress the intensity of heat transfer. Data were obtained on the air flow rate and the local heat transfer coefficient both in the exhaust duct of the turbocharger compressor (i.e., without a piston engine) and in the intake system of a supercharged engine. A comparative analysis of the data has been carried out. It was found that the installation of a leveling grid in the exhaust channel of a turbocharger leads to an intensification of heat transfer by an average of 9%. It was found that the presence of a leveling grid in the intake system of a piston engine causes the suppression of heat transfer within 15% in comparison with the baseline values. It is shown that the use of a modernized intake system in a diesel engine increases its probability of failure-free operation by 0.8%. The data obtained can be extended to other types and designs of air supply systems for heat engines.

Compressed air supply system of vibro‐isolated tools

1992 ◽  
Vol 91 (5) ◽  
pp. 3083-3083
Author(s):  
Marian W. Dobry ◽  
Czeslaw Cempel ◽  
Wieslaw Garbatowski
Keyword(s):  
Supply System ◽  
Compressed Air ◽  
Air Supply

scholarly journals Thermal Comfort and Energy Analysis of a Hybrid Cooling System by Coupling Natural Ventilation with Radiant and Indirect Evaporative Cooling

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7825
Author(s):  
Pradeep Shakya ◽  
Gimson Ng ◽  
Xiaoli Zhou ◽  
Yew Wah Wong ◽  
Swapnil Dubey ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Hybrid System ◽  
Natural Ventilation ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Supply System ◽  
Hybrid Cooling ◽  
Air Supply ◽  
Radiant Cooling ◽  
Indirect Evaporative Cooling

A hybrid cooling system which combines natural ventilation with a radiant cooling system for a hot and humid climate was studied. Indirect evaporative cooling was used to produce chilled water at temperatures slightly higher than the dew point. With this hybrid system, the condensation issue on the panel surface of a chilled ceiling was overcome. A computational fluid dynamics (CFD) model was employed to determine the cooling load and the parameters required for thermal comfort analysis for this hybrid system in an office-sized, well-insulated test room. Upon closer investigation, it was found that the thermal comfort by the hybrid system was acceptable only in limited outdoor conditions. Therefore, the hybrid system with a secondary fresh air supply system was suggested. Furthermore, the energy consumptions of conventional all-air, radiant cooling, and hybrid systems including the secondary air supply system were compared under similar thermal comfort conditions. The predicted results indicated that the hybrid system saves up to 77% and 61% of primary energy when compared with all-air and radiant cooling systems, respectively, while maintaining similar thermal comfort.

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