Effect of Inlet Clearance on the Aerodynamic Performance of a Centrifugal Blower
-
C. Hariharan
und
M. Govardhan
Abstract
The present work reports the effect of inlet clearance on the performance of a centrifugal blower, with parallel wall volute, over its full operating range. For a particular impeller configuration, four volutes based on constant angular momentum principle, have been designed and analysed numerically for varying inlet clearances ranging from 0 mm (ideal clearance) to 5 mm. The computational methodology is validated using experimental data. The results indicate that as the clearance increases, the impeller performance in terms of both static and total pressure rise deteriorate. Further, the stage performances deteriorate in terms of efficiency and specific work for all mass flow rates. However, the performance of volute improves at lower mass flow rates compared to the Best Efficiency Point (BEP). A set of correlations have been developed to predict the change in stage performance as a function of clearance ratio. The non-dimensional values of change in specific work, isentropic efficiency and static pressure are found to be same irrespective of the shape of the volute.
Nomenclature
- Cp
pressure recovery coefficient
- m
mass flow rate (kg/s)
- mc
return mass flow rate (kg/s)
- P
static pressure (N/m2)
- P0
total pressure (N/m2)
- C∆P3
change in static pressure at impeller exit (%)
- C∆P03
change in total pressure at impeller exit (%)
- C∆P5
change in static pressure at volute exit (%)
- Q
volume flow rate (m3/s)
- V⊤
through flow velocity (m/s)
- W
isentropic specific work (m2/s2)
- C∆W
change in isentropic specific work (%)
- Z/B
ratio of axial position to blade height
- α
flow angle with respect to tangential direction (deg.)
- η
Total to Toal isentropic efficiency of stage (%)
- C∆η
change in isentropic efficiency (%)
- θ
angular position with respect to tongue (deg.)
- τ
inlet clearance ratio (ratio of radial clearance to impeller inlet radius)
- ρ
density (kg/m3)
- φ
angle between successive blades (deg.)
- Cω
volute loss flow coefficient
- Subscripts
- 0
inlet of suction duct
- 1
exit of suction duct
- 2
inlet of impeller
- 3
exit of impeller
- 4
inlet to volute
- 5
exit of volute
- d
design value
Abbreviations
- B2
impeller exit width (m)
- B5
volute exit width (m)
- R 3.0
Ratio of volute width to impeller width = 3.0
- R 3.5
Ratio of volute width to impeller width = 3.5
- R 4.0
Ratio of volute width to impeller width = 4.0
- R 5.0
Ratio of volute width to impeller width = 5.0
- τ0
inlet clearance ratio of 0 mm
- τ1
inlet clearance ratio of 1 mm
- τ2
inlet clearance ratio of 3 mm
- τ3
inlet clearance ratio of 5 mm
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©2016 by De Gruyter
Artikel in diesem Heft
- Frontmatter
- Experimental Investigation on the Ignition Delay Time of Plasma-Assisted Ignition
- Effect of Inlet Clearance on the Aerodynamic Performance of a Centrifugal Blower
- Alternative Method to Simulate a Sub-idle Engine Operation in Order to Synthesize Its Control System
- Aerodynamic Design and Numerical Analysis of Supersonic Turbine for Turbo Pump
- A Comparison of Hybrid Approaches for Turbofan Engine Gas Path Fault Diagnosis
- Optimization of a Turboprop UAV for Maximum Loiter and Specific Power Using Genetic Algorithm
- Taguchi Based Regression Analysis of End-Wall Film Cooling in a Gas Turbine Cascade with Single Row of Holes
- Numerical Investigation of Cowl Lip Adjustments for a Rocket-Based Combined-Cycle Inlet in Takeoff Regime
Artikel in diesem Heft
- Frontmatter
- Experimental Investigation on the Ignition Delay Time of Plasma-Assisted Ignition
- Effect of Inlet Clearance on the Aerodynamic Performance of a Centrifugal Blower
- Alternative Method to Simulate a Sub-idle Engine Operation in Order to Synthesize Its Control System
- Aerodynamic Design and Numerical Analysis of Supersonic Turbine for Turbo Pump
- A Comparison of Hybrid Approaches for Turbofan Engine Gas Path Fault Diagnosis
- Optimization of a Turboprop UAV for Maximum Loiter and Specific Power Using Genetic Algorithm
- Taguchi Based Regression Analysis of End-Wall Film Cooling in a Gas Turbine Cascade with Single Row of Holes
- Numerical Investigation of Cowl Lip Adjustments for a Rocket-Based Combined-Cycle Inlet in Takeoff Regime
