Drag Reduction in a 90-degree Bend Pipe with a Half-Trip.

Takamura

et al. 2014

JFST

T-junction pipes are frequently used in industrial facilities to split one flow into two flows or to merge two flows into one flow. In the counter-flow type of confluence in this type of pipe, separated vortex flow regions are formed near the junction corners and these regions cause a large flow resistance. The corners of a T-junction pipe are generally made round to avoid flow separation and to reduce the flow resistance or loss, but this method requires a junction corner removal process. In this study, we mount small weir-shaped obstacles on the walls of pipes upstream of the junction corner to reduce the loss. We examine the effect of the flow rate ratio on the loss and clarify the obstacle height and position conditions that reduce the loss for a wide range of flow rate ratio.

Section: Effects Of Flow Rate Ratio On Loss Reduction Of -Junction Pipementioning

confidence: 99%

Effects of flow rate ratio on loss reduction of T-junction pipe

Takamura

et al. 2014

JFST

“…In general, the corners of T-junction pipe are made round in order to avoid the flow separation and to reduce the flow resistance or loss, but this method needs a removal process, which reduce the thickness of pipe, for junction corner. There is a study which propose the simple method of mounting small obstacle in order to reduce loss of the pipes or ducts with abrupt changes to cross-sectional areas by Mochizuki et al [6] and Ando et al [7]- [10].…”

Section: Introductionmentioning

confidence: 99%

1108 Effects of Flow Rate Ratio on Loss Reduction of T-Junction Pipe

Takamura

et al. 2013

ICJWSF

T-junction pipes are frequently used in the industrial facilities in order to split one flow into two flows or join two flows into one flow. In the counter-flow type confluence of in this type of pipe, separated vortex flow regions near the corners of junction are formed and these regions cause to large flow resistance. In general, the corners of T-junction pipe are made round in order to avoid the flow separation and to reduce the flow resistance or loss, but this method needs a removal process for junction corner. In this study, we mount weir shaped small obstacles on the walls of pipes of upstream of junction corner in order to reduce the loss. We examine the effect of the flow rate ratio on the loss, and made clear the condition of obstacle height and position which reduces the loss for wide range of flow rate ratio.

“…• bend of a circular pipe by mounting a half trip on the pipe wall (5) . The authors clarified that the flow resistance in abrupt contractions of circular pipes and pipe inlets could be reduced by mounting small obstacles near the corner to suppress the vortex region (6)- (9) .…”

Section: Introductionmentioning

confidence: 99%

“…Figure 2 has a schematic of the experimental set up. The water in the reservoir (1) was pressurized by the pump (2), divided into two flows, controlled by the valve (3), measured with the flow meter (4), and introduced into the test section (5). The test section (5) was made of transparent acrylic resin, consisting of three straight pipes that had circular cross sections with a diameter of D = 30[mm] and it was placed horizontally.…”

Section: Introductionmentioning

confidence: 99%

Drag Reduction of T-junction Pipe Flow by Small Obstacles

Nishibata

et al. 2011

JFST

Flows in the T-junction of a counter-flow pipe are run counter to each other and they usually flow out vertically together. A flow separated from the junction corner forms separated vortex regions and they reduce the effective cross-sectional areas of the pipe, and this increases flow resistance, i.e., drag (pressure loss). The corner of the junction is generally rounded to prevent the flow from separating and to reduce drag. This method can reduce drag by 30% with a rounded radius of 0.1D (D: pipe inner diameter), but some process is needed to remove the corners. We propose a simple method of reducing drag in the flows of T-junction pipes by mounting two small weir-shaped obstacles on the upstream of the walls of the two pipes beside the junction corners. This method is a simple way of reducing drag without having to use a removal process. The pressure distribution along the pipes was measured and the drag in a T-junction pipe was derived. The flow pattern was visualized with a tracer method and this was evaluated to confirm the separation of flow from the corners. As a result, we clarified that drag in a T-junction could be reduced by a maximum of about 30% by mounting small obstacles at heights of 0.30D and 0.47D from the upstream of the corners.