A Regenerative Compressor

Abstract

A regenerative or peripheral compressor has been developed with aerodynamic blading in place of the usual straight radial vanes on the rotor. The blades are shrouded by a core, around which a helical toroidal flow path is established. Two compressors have been constructed, the first with a single row of blades and the second with two rows side by side to provide parallel counterrotating flow paths. The diameter of the impellers is 0.30 m. The characteristics of the compressor resemble those of a Rootes blower, with a steep variation of pressure with respect to flow rate. At a speed of 4000 rpm the isothermal efficiency reaches a maximum of 57 percent when the pressure ratio is 1.17 and the flow rate is 0.2 m3/s. When the flow rate is reduced by throttling to 0.165 m3/s the pressure ratio is raised to 1.50, but the isothermal efficiency is reduced to 44 percent. The theory, design, and development of the compressor are discussed.

Design optimisation of a regenerative pump using numerical and experimental techniques

“…A different approach would be required to consider compressibility of the fluid, e.g. in regenerative blowers (Hollenberg and Potter, 1979;Sixsmith and Altmann, 1977), but for the current analysis where the fluid is treated as incompressible, then use of MRF at multiple fixed rotor positions is a suitable and a recommended approach (FLUENT, 2001(FLUENT, , 2005(FLUENT, , 2006a. For modeling turbulence, realizable k 2 1 was chosen (Spalart, 2000;Shih et al, 1995), for the regenerative pump as it is suitable for complex shear flows involving rapid strain, swirl, vortices and locally transitional flows (boundary layer separation and vortex shedding).…”

Regenerative liquid ring pumps review and advances on design and performance

“…The highest reported efficiency for any water-ring self-priming pump was measured by Crewdson in 1956 [21] at 50%. The low efficiency can partly be assigned to the inherent fluid dynamic behaviour of the pump; the input power is used for developing the increase in head as well as being consumed by the circulatory flow through the impeller blades [15,32,52]. However, the pumping efficiency is significantly reduced when the circulatory flow decreases [21].…”

“…As much as 40-50% of the supplied power is believed to be consumed losses that are related to the geometry of the machine [53], of which losses due to slip make up the largest contribution [52,54]. The performance of the RLR pump is also affected by other types of losses, such as shock losses, circulation losses, peripheral friction losses, losses at the inlet and outlet ports and leakage losses [5] [ 12,15,53], which are explained in more detail in the subsequent sections.…”

“…To avoid excessive backflow the stripper clearance must be kept to a minimum. However, Sixsmith & Altmann [52] believed that only small improvements in performance could be gained. Sixsmith [54] later identified that mulitstaging could reduce the loss of efficiency due to the backflow by nearly a half.…”

“…This is probably why this type is the most common form used for commercial units [28,58]. Symmetrical blade profiles have also been shown to increase the efficiency due to improved energy transfer between the impeller and the fluid [52]. This can be assigned to the reduction of so called "dead zones" of fluid between adjacent blades which do not take part in the circulation [59].…”