Energy Loss of Three-Dimensional Flow

• Project/Area Number: 61550132
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Fluid engineering
• Research Institution: KYUSHU UNIVERSITY
• Principal Investigator: KINOSHITA Yoshifumi (1987) Institute of Advanced Material Sutdy of Kyushu University, 機能物質科学研究所, 助教授 (70037977); 妹尾 泰利 (1986) 九大, 生産科学研究所, 教授 (10038573)
• Co-Investigator(Kenkyū-buntansha): HAYAMI Hiroshi Institute of Advanced Material Study of Kyushu University, 機能物質科学研究所, 教授 (10038606) ; 木下 凱文 九州大学, 生産科学研究所, 助手 (70037977)
• Project Period (FY): 1986 – 1987
• Project Status: Completed (Fiscal Year 1987)
• Budget Amount: ¥1,800,000 (Direct Cost: ¥1,800,000); Fiscal Year 1987: ¥200,000 (Direct Cost: ¥200,000); Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
• Keywords: Three-dimensional flow / Energy loss / Deceleration loss / Accumulation of boundary layer / Curved channel / 三次元平衡境界層 / 二次元流れ / 曲り通路 / 曲り損失

Research Abstract

The energy loss of the flow in a bend and in a casscade in usually much larger than the simple energy loss due to wall friction based on a two-dimensional flow. This large energy loss has been considered due to the flow complexity based on a three dimensional flow. Energy loss of three dimensional flow consists of various losses due to friction, deceleration, mixing of flow and secondary flow. In order to clarify the mechanism of energy loss of three-dimensional flow, the flow in a 200 deg curved channel with rectangular corss-section was investigated in detail. To pay attention on a deceleration loss mechanism, the deceleration rate along the inner wall was varied in three ways including no deceleration by changing the width of channel passage toward the exit of the curved channel. Adding to the measurement of wall static pressure distribution along the curved walls, the midway of the curved channel and the sedtion II was the exit straight part of the channel. The equilibrium cross flow boundary layer on the end wall was confirmed by comparing with the prediction at the section I. A roll up vortex and an accumlation of boundary layer were observed at both sections I and II.
The loss of total pressure between the section I and the section II was increased at the decelation rate was increased. In the present case, the maximum loss coefficient was 1.6 times as much as that of no deceleration. That is, the deceleration loss is the major part of the energy loss of three dimensional flow. This implies that the energy loss of three dimensional flow can be decreased by controlling the deceleration rate.