• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.801-806
• /
• 2001

The objective of present study is to find the interaction between volute and impeller of the centrifugal turbomachinery with rectangular cross-sectional volute. Flow measurement were taken in shrouded impeller with 12 backward type blades by using a five-hole pressure probe. The measurements are carried out in 7 flow rate, respectively. Primary function of a centrifugal turbo machinery volute is to serve the flow from the impeller and diffuser to pipe system. For the off-design conditions, Influence of pressure distortion was shown by these measurements. As a result, It has caused the decrease of total efficiency of centrifugal turbomachinery. We have also taken data to design volute by these measurements.

• Proceedings of the KSME Conference
• /
• 2002.08a
• /
• pp.623-626
• /
• 2002

The object of present study is to find the flow characteristics of centrifugal turbomachinery according to the volute shape change. The experiments were carried out for two model; volute-A designed by free vortex conditions and volute-B designed for use in high mass flow rate conditions using the volute-A test results, Flow measurements were taken in shrouded impeller with 12 backward type blades by using a five-hole pilot-tube and carried out in 4 flow rate, $Q/Q_d\;=0,43,\;1.0,\;1.27,\;1,47$, respectively, For volute-B, we found that pressure distribution was more uniform at high flow rate and from $Q/Q_d\;:\;0,43\;to\;Q/Q_d\;:\;1,20$, losses decreased and efficiency increased compare with volute-A.

• 유체기계공업학회:학술대회논문집
• /
• 2000.12a
• /
• pp.219-225
• /
• 2000

Primary function of a centrifugal compressor volute is to serve the flow from the impeller and diffuser to pipe system. But losses in volutes at off-design lead to poor stage efficiency and reduction of operating range. This is largely caused by the interaction between the impeller and volute flow fields. The magnitude of distortion is increased as the operating point is away from the design point and, as a result, the interaction between the impeller and volute is stronger. The objective of present study is to find the characteristics of tile flow in the diffuser and volute of the centrifugal compressor with rectangular cross-sectional volute. The measurements are carried out in two cases with the existence and nonexistence of the volute casing. The detailed pressure is presented by comparing the experimental results obtained at two cases with each others.

• 유체기계공업학회:학술대회논문집
• /
• 1999.12a
• /
• pp.170-178
• /
• 1999

In general, an impeller of centrifugal turbomachinery is designed at isolated condition without considering the presence of a volute, but when the impeller is operating with its volute, the performance of impeller can be different. This is largely caused by the interaction between the impeller and volute flow fields. The magnitude of distortion is increased as the operating point is away from the design point and, as a result, the interaction between the impeller and volute is stronger. In the present calculation, the flow through the impeller is simulated using coarse grids. The flow within the impeller and the volute is naturally unsteady, but the flow is assumed to be steady across the interface between the volute and impeller flow fields. Under the assumption of steady three-dimensional incompressible turbulent flow, the time averaged N-S equations involving standard k-$\epsilon$ turbulent model was solved by the F.V.M. The calculation results are compared with the experimental results obtained for an industrial fan by Sakai etc. and the Hood agreement is demonstrated. And the effects of the impeller-volute interaction are studied.

• Journal of computational fluids engineering
• /
• v.1 no.1
• /
• pp.35-46
• /
• 1996

원심형 임펠러 내부 유로등 큰 곡률을 수반하는 터보기계 요소의 유동해석을 위한 계산코드를 개발하였다. 이 코드에서는 곡선좌표계에 유도된 3차원 비압축성 Navier-Stokes의 운동 방정식을 SMAC 음해법으로 푼다. 이 코드를 이용하여 유로의 단면이 정사각형이고 90도로 굽은 덕트내부의 층류 입구유동을 해석하고, 굽은 관 특유의 유동현상을 수치모사하였다 또한 곡관부 입구에서 충분히 발달한 유동, 또는 발달중인 유동이 유입될 경우에 이것이 곡관부 내부의 유동에 미치는 영향을 상·하류의 계산영역이 서로 다를 몇몇 유동장에 대하여 조사하고, 본 계산에서 얻어진 결과와 실형결과와의 비교로 본 3차원 유동해석 코드의 유효성을 검토 하였다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.10
• /
• pp.1083-1088
• /
• 2011

The effects of an impeller and floating ring seals on the performance of centrifugal pumps are investigated on the basis of their test results using water. The pumps are single-staged centrifugal pumps developed for 30-ton- and 75-ton-class liquid rocket engines, and are components of a turbopump that supplies propellants (liquid oxidizer and kerosene) to the combustion chamber. The exit width of the impellers and the numbers and exit angles of the impeller blades are found to have influences on the pump heads. In addition, the pumps have different efficiencies according to the gaps between the floating ring seals and the impellers, whereas the pump size seems to have less effect on the efficiency.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.813-818
• /
• 2001

The flow characteristics of the vaned diffuser were complicated with geometric shapes. We have studied the effects of various vaned diffuser configurations, such as divergence angles and rectangular and conical cross-section shapes. Numerical analyses are carried out for the diffuser and casing. The pressure recovery coefficient was calculated to estimate the performance of the diffuser, and then compared with the measure data. Results show that the shapes and the divergence angles of the diffuser strongly influence on the performance of the small-size turbo-compressor.

• The KSFM Journal of Fluid Machinery
• /
• v.19 no.4
• /
• pp.5-12
• /
• 2016

In this study, a parametric study on a cavity as casing treatment of a centrifugal compressor has been conducted using three-dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model. Two kinds of cavity were applied at choke and surge conditions, respectively, in this work. Inlet and outlet port widths, angle of outlet port, and length of cavity were chosen as the geometric parameters and investigated to find their effects on the aerodynamic performances such as adiabatic efficiency at design mass flow rate and stall margin of the centrifugal compressor. It was found that the aerodynamic performances of the centrifugal compressor were affected considerably by the four geometric parameters. The adiabatic efficiency was hardly changed by the geometric parameters, excepts for the angle of outlet port. With an increase in the angle of outlet port, the adiabatic efficiency and the stall margin decreased. The stall margin was more sensitive to the outlet port width than to the other geometric parameters. And, with a decrease in the outlet port width, the stall margin increased by 2% compared to that of the reference.

• The KSFM Journal of Fluid Machinery
• /
• v.17 no.5
• /
• pp.43-53
• /
• 2014

This paper presents a the study on air curtain system of top and bottom bi-directional jet air discharge for blocking the spread of smoke in case of tunnel fire. The five kinds different air curtains of A, B, C, D, and E of models for various performance tested after manufactured. A results of the various performance test obtained the best efficiency from E model air curtain. And optimize the injection angle of the air curtain nozzle through the three-dimensional computational fluid dynamics (CFD) analysis and analyzed the effects of external pressure of tunnel. and also single factor design have been applied. At present, our attention is focused on the velocity distribution(flow width and flow position) of 1.5m on the ground in tunnel. Also, analyzed the influence of draft in the tunnel. Detailed effects of discharge angle of air curtain and velocity at nozzle exit are discussed.