Experimental analysis of engine cooling capacity at different altitudes: a case study for biarticulated gas engine bus at high altitude

2020 ◽  
Author(s):  
Gabriel Prado de Oliveira ◽  
Bruno Afonso Garcia
Keyword(s):  
High Altitude ◽  
Experimental Analysis ◽  
Cooling Capacity ◽  
Gas Engine ◽  
Engine Cooling ◽  
Different Altitudes

Influence of Altitude on the Performance of a Bicycle-Cyclist Set

2017 ◽  
Author(s):  
Mateo Morales ◽  
Sergio D. Roa ◽  
Luis E. Muñoz ◽  
Diego A. Ferreira ◽  
Omar D. Lopez Mejia
Keyword(s):  
High Altitude ◽  
Drag Force ◽  
Power Output ◽  
Aerodynamic Drag ◽  
Integrated Approach ◽  
Cycling Performance ◽  
Air Density ◽  
Effort Tests ◽  
Different Altitudes

There is a tradeoff between power delivery and aerodynamic drag force when cyclists ride at different altitudes. The result is particular to the characteristics of the bicycle as well as the aerobic fitness of the cyclist. This work proposes a methodology based on an integrated approach to the study of the influence of altitude on power output and aerodynamic drag over a particular bicycle-cyclist set. The methodology consists of an independent analysis for each of the effects, to conclude with an integration of results that allows estimating the overall effect of altitude on cycling performance. A case study for the application of the methodology was developed, and the obtained results apply for the specific bicycle-cyclist set under analysis. First, the relationship between power and time was analyzed for a male recreational cyclist based on all-out effort tests at two different altitudes: 237 meters and 2652 meters above sea level (m.a.s.l). Second, the effects of environmental conditions on air density and drag area coefficient due to altitude changes were analyzed based on Computational Fluid Dynamics (CFD) simulations. It was found that for the bicycle-cyclist set under study, the sustainable power output for 1-hour cycling was reduced 45W for the high-altitude condition as a consequence of the reduction in the maximum oxygen uptake capacity. In addition, the aerodynamic drag force is reduced in greater proportion due to the change in air density than due to the change in drag coefficient. Finally, the results of both effects were integrated to analyze the overall influence of altitude on cycling performance. It was found that for the analyzed case study, the aerodynamic advantage at higher altitude dominates over the disadvantage of reduction in power output: despite delivering 45W less, the subject can travel an additional distance of 900 meters during a one hour ride for the high-altitude condition compared to that in low altitude.

ASU Simulation in Separating Air Components by Refrigeration Distillation (Oxygen and Nitrogen) Using ASPEN HYSYS (Case Study: SIAD Company)

2020 ◽  
Vol 15 (3) ◽  
Author(s):  
Afshar Alihosseini
Keyword(s):  
Cooling Capacity ◽  
Air Separation ◽  
Cooling Power ◽  
Distillation Tower ◽  
Aspen Hysys ◽  
Expansion Turbine ◽  
Gas Products ◽  
Utility Services ◽  
Petrochemical Industries

AbstractCurrently, air separation units (ASUs) have become very important in various industries, particularly oil and petrochemical industries which provide feed and utility services (oxygen, nitrogen, etc.). In this study, a new industrial ASU was evaluated by collecting operational and process information needed by the simulator by means of HYSYS software (ASPEN-ONE). The results obtained from this simulator were analyzed by ASU data and its error rate was calculated. In this research, the simulation of ASU performance was done in the presence of an expansion turbine in order to provide pressure inside the air distillation tower. Likewise, the cooling capacity of the cooling compartment and the data were analysed. The results indicated that expansion turbine is costly effective. Notably, it not only reduces the energy needed to compress air and supply power of the equipment, but also provides more cooling power and reduces air temperature. Moreover, turbines also increase the concentration of lighter gas products, namely nitrogen.

scholarly journals A Probabilistic Target Search Algorithm Based on Hierarchical Collaboration for Improving Rapidity of Drones

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2535 ◽  
Author(s):  
Il-Kyu Ha ◽  
You-Ze Cho
Keyword(s):  
High Altitude ◽  
Target Detection ◽  
Information Transfer ◽  
Search Algorithm ◽  
Search Time ◽  
Previous Method ◽  
Target Search ◽  
Low Altitude ◽  
Military Facilities ◽  
Different Altitudes

Finding a target quickly is one of the most important tasks in drone operations. In particular, rapid target detection is a critical issue for tasks such as finding rescue victims during the golden period, environmental monitoring, locating military facilities, and monitoring natural disasters. Therefore, in this study, an improved hierarchical probabilistic target search algorithm based on the collaboration of drones at different altitudes is proposed. This is a method for reducing the search time and search distance by improving the information transfer methods between high-altitude and low-altitude drones. Specifically, to improve the speed of target detection, a high-altitude drone first performs a search of a wide area. Then, when the probability of existence of the target is higher than a certain threshold, the search information is transmitted to a low-altitude drone which then performs a more detailed search in the identified area. This method takes full advantage of fast searching capabilities at high altitudes. In other words, it reduces the total time and travel distance required for searching by quickly searching a wide search area. Several drone collaboration scenarios that can be performed by two drones at different altitudes are described and compared to the proposed algorithm. Through simulations, the performances of the proposed algorithm and the cooperation scenarios are analyzed. It is demonstrated that methods utilizing hierarchical searches with drones are comparatively excellent and that the proposed algorithm is approximately 13% more effective than a previous method and much better compared to other scenarios.

Experimental Analysis of a Laboratory-Scale Diesel Engine Exhaust Heat-Driven Absorption Refrigeration System as a Model for Naval Surface Ship Applications

2020 ◽  
Vol 36 (02) ◽  
pp. 152-159 ◽  
Author(s):  
Cüneyt Ezgi ◽  
Sinem Bayrak
Keyword(s):  
Diesel Engine ◽  
Experimental Analysis ◽  
Alternative Energy ◽  
Cooling Capacity ◽  
Energy Sources ◽  
Naval Academy ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Exhaust Heat ◽  
Absorption Refrigeration System

Decreasing industrial energy sources and major environmental problems caused by uncontrolled energy consumption have led to studies on alternative energy sources. This study presents a design and experimental analysis of an exhaust gas-driven absorption refrigeration system for the purpose of air conditioning by using the exhaust heat of a diesel engine, which is installed in the Naval Academy Mechanics Laboratory. The diesel engine is loaded with a dynamometer, and water and ammonia are used as an absorbent and refrigerant, respectively. At various diesel engine loads, cooling capacity and coefficient of performance (COP) of the absorption refrigeration system are calculated. Experimental results have indicated the cooling capacity as 1.098 kW at a maximum engine power of 4.9 HP. The highest COP value in the designed system has been calculated to be .3022 for the generator temperature of 160 C. Although the COP of refrigeration is low, the absorption refrigeration system can be provided a great cooling load from the exhaust heat of diesel engines and can be used in naval surface ships. In addition to energy efficiency of naval surface ships, infrared and acoustic signature can be minimized and a ships susceptibility can be dramatically reduced.

scholarly journals Impact of High-Altitude on Truck’s Climbing Speed: Case study in Qinghai-Tibet Plateau Area in China

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Tian Lei ◽  
Jinliang Xu ◽  
Xingli Jia ◽  
Leyu Wei ◽  
Lin Tian
Keyword(s):  
High Altitude ◽  
Traffic Safety ◽  
Field Tests ◽  
Tibet Plateau ◽  
Infrastructure Development ◽  
Plateau Area ◽  
Negative Effect ◽  
High Altitude Area ◽  
The Impact ◽  
Different Altitudes

Truck’s climbing performance is an important consideration in traffic safety, efficiency, and highway geometric design. With the infrastructure development in high-altitude area in China, more attention needs to be paid on truck’s climbing performance in such area. In this article, truck’s climbing speed in high-altitude area was examined through field tests on different grade sections at different altitudes. Truck’s speed-distance curves were built at different altitudes and the impact of altitude on truck’s climbing speed was explored based on the test results. It was shown that, within the altitude range of 3000~5000m, altitude had an obvious influence on test truck’s decelerating and accelerating performance. Truck’s speed decreased faster on steep grades and increased slower on gentle grades with the increase of the altitude. Also, the stable speed that test truck could maintain on a certain grade was lower at a higher altitude. In addition, test truck’s theoretical speed-distance curves at the sea level were estimated through truck’s dynamic model. Compared with the theoretical crawl speed, a negative effect of altitude change (from 0 to the altitude above 3000 m) was found on truck’s climbing performance.

scholarly journals Conversion of gas engine waste heat into cold using absorption chillers

2020 ◽  
Vol 168 ◽  
pp. 00046
Author(s):  
Georgii Karman ◽  
Yurii Oksen ◽  
Olena Trofymova ◽  
Yurii Komissarov ◽  
Borys Dizhevskyi ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Waste Heat ◽  
Lithium Bromide ◽  
Thermodynamic Cycle ◽  
Cooling Capacity ◽  
Coolant Temperature ◽  
Gas Engine ◽  
Absorption Chillers ◽  
Full Conversion ◽  
Heating Medium

A possibility of gas engine waste heat conversion into cold for air conditioning in mines using lithium bromide absorption chillers is investigated. Dependencies of parameters of a thermodynamic cycle and energy indicators of chillers on temperatures of a heating medium and a coolant are obtained using mathematical modelling. It is shown that it is rational to use two chillers with sequential movement of a heating medium and a coolant through them in opposite directions for a full conversion of gas engine waste heat. COP of such a system is 0.733. This allows obtaining 2140 kW of cooling capacity with a coolant temperature of 7 °C when using a gas engine JMS-620 by Jenbacher.

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