Tumbling/squish interaction in loop-scavenged two-stroke engines

Journal Article · Mon Dec 01 04:00:00 EST 1997 · Numerical Heat Transfer. Part A, Applications

DOI:https://doi.org/10.1080/10407789708913921· OSTI ID:596788

Tsui, Y Y; Cheng, H P ^[1]

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1. National Chiao Tung Univ., Hsinchu (Taiwan, Province of China). Dept. of Mechanical Engineering

This article describes a numerical investigation of the flow in a loop-scavenged two-stroke engine equipped with a head-bowl combustion chamber. The bowl is either placed in the center of the cylinder head or displaced away from the center. Attention is focused on the period of compression and early expansion. Results show that the effects of compression of the tumbling vortex by the piston become prominent after the midcompression stage, resulting in significant cascading of energy from mean flow to turbulence, followed by a fast decay of turbulence. The subsequent emergence of squish and reverse squish helps retard the decay. As a consequence, the cases with head bowls possess higher levels of mean flow and turbulence than those without bowls at top dead center and the later stage. It is also shown in the results that the offset of the head bowl had significant effects on the mean flow and turbulence characteristics, highly dependent on the offset direction.

• Sponsoring Organization: USDOE
• OSTI ID: 596788
• Journal Information: Numerical Heat Transfer. Part A, Applications, Journal Name: Numerical Heat Transfer. Part A, Applications Journal Issue: 8 Vol. 32; ISSN 1040-7782; ISSN NHAAES
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
COMBUSTION CHAMBERS
DIESEL ENGINES
FLUID FLOW
NUMERICAL ANALYSIS
TURBULENT FLOW
VORTEX FLOW