scholarly journals Numerical Study on Transfer Port Design for Scavenging Performance in Small Two-stroke Engines

2020 ◽  
Vol 24 (6) ◽  
pp. 28-44
Author(s):  
Cheonghwan Kim ◽  
Sungho Park ◽  
Myeongkyu Kim ◽  
Eunsoo Ahn
Keyword(s):  
Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2362
Author(s):  
Savvas Savvakis ◽  
Dimitrios Mertzis ◽  
Elias Nassiopoulos ◽  
Zissis Samaras

The current paper investigates two particular features of a novel rotary split engine. This internal combustion engine incorporates a number of positive advantages in comparison to conventional reciprocating piston engines. As a split engine, it is characterized by a significant difference between the expansion and compression ratios, the former being higher. The processes are decoupled and take place simultaneously, in different chambers and on the different sides of the rotating pistons. Initially, a brief description of the engine’s structure and operating principle is provided. Next, the configuration of the compression chamber and the sealing system are examined. The numerical study is conducted using CFD simulation models, with the relevant assumptions and boundary conditions. Two parameters of the compression chamber were studied, the intake port design (initial and optimized) and the sealing system size (short and long). The best option was found to be the combination of the optimized intake port design with the short seal, in order to keep the compression chamber as close as possible to the engine shaft. A more detailed study of the sealing system included different labyrinth geometries. It was found that the stepped labyrinth achieves the highest sealing efficiency.


1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,

2020 ◽  
pp. 57-65
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Xavier Viegas ◽  
...  

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.


2013 ◽  
Author(s):  
Pancheewa Benjamasutin ◽  
◽  
Ponthong Rijana ◽  
Phongchayont Srisuwan ◽  
Aussadavut Dumrongsiri

2013 ◽  
Author(s):  
Artchapong Hassametto ◽  
Preerawadee Chaiboontun ◽  
Chattraporn Prajuabwan ◽  
Laphatrada Khammuang ◽  
Aussadavut Dumrongsiri

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