Annular-Sector Concave Blade Impeller Gas-Liquid Dispersion
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Solution Overview
Problem
Existing gas-liquid dispersion impellers, such as the Rushton turbine, suffer from low power efficiency and gas flooding issues due to low-pressure trailing vortices, leading to energy dissipation and reduced mass transfer efficiency.
Innovation Solution
The design of an annular-sector-shaped concave blade impeller, where the upper portion has a larger arc length than the lower portion, eliminates excessive protrusions and enhances bubble capture, improving gas-liquid dispersion and mixing performance while reducing power consumption and cavitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of the blade is increased to improve radial pump capacity, then the radial pump capacity is improved, but the diameter of the leading vertex on the outer edge becomes much larger than that of the trailing vertex, producing large moment and power consumption
Solution Approach 1:
The blade cross-section is designed with asymmetric curvature radii: the inner edge (near the shaft) has a larger curvature radius while the outer edge has a smaller curvature radius. This asymmetric design allows the blade to maintain effective pumping capacity without creating excessive protrusions at the outer edge, thereby reducing the moment and power consumption while preserving radial pump capacity.
2Use of energy by moving object
If deeper concave blades are used to reduce power consumption, then power consumption is reduced, but the radial pump capacity is largely reduced
Solution Approach 1:
The blade design applies different curvature characteristics to different regions: the inner portion near the shaft has a larger curvature radius to reduce power consumption and avoid excessive protrusions, while the outer portion maintains appropriate dimensions to preserve radial pump capacity. This localized differentiation of geometric properties resolves the contradiction between energy efficiency and pumping performance.
3Productivity
If the blade width is increased to improve radial pump capacity, then the radial pump capacity is improved, but excessive protrusions are generated on the periphery of the blade, increasing power consumption
Solution Approach 1:
By designing the blade with asymmetric curvature radii where the inner edge has a larger radius and the outer edge has a smaller radius, the blade achieves effective pump capacity without generating excessive protrusions at the periphery. This asymmetric geometry controls the blade outline to avoid harmful protrusions while maintaining productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The annular-sector-shaped blade impeller achieves higher gas flow rates, improved gas holdup, and enhanced mixing efficiency with lower power consumption, effectively addressing the limitations of traditional impellers.
Implementation Method 1
the upper front edge of a blade tangentially extends and exceeds the lower front edge of the blade; in this way, the blade can capture more bubbles
Implementation Method 2
each part of the blade directly faces an incoming flow, so that the fluid is pumped radially
Implementation Method 3
the disc can collect bubbles below the impeller and guide the bubbles into a high-shear blade area, thereby achieving good gas-liquid dispersion
Implementation Method 4
low-pressure trailing vortexes easily occur at the back of the blades during the operating of the Rushton turbine
Implementation Method 5
the low-pressure core of the trailing vortex attracts bubble coalescence and gas cavities are formed at the back of the blades
Data Source
AI summary
The invention discloses an agitation device comprising an impeller, an agitating shaft and a power device. The impeller includes a disc, a hub and concave blades. Each blade consists of a concave surface which extends radially and has an annular sector-like shape, the projections of the upper and lower portions of the blade in the horizontal plane are two annular sectors, and the radian of the annular sector obtained by the projection of the upper portion is larger than that of the lower portion, and the annular sector-like shape and the rotation direction of blades are the same, so that each portion of the blades directly faces an incoming flow, the utilization efficiency of blades is increased and the impeller has low energy consumption and high gas-liquid dispersion efficiency. The device is efficient and energy-saving, has low power consumption, high mixing performance and high gas holdup and mass transfer performance.