Compressor  AVC  Expander Gas Turbine Engine

Compressor


The Rampressor

Ramgen's primary technical innovation has been to apply ramjet engine concepts in a stationary compressor application as illustrated below.


Ramgen's core design, the Rampressor, is a relatively simple device. It features a rotating disk, which operates at the high peripheral speeds necessary to achieve supersonic effect in a stationary environment. The rim of the disk has three raised sections and cavities that mimic the effect of the center-body and channels of a conventional ramjet inlet. Air enters through a common inlet and is then ingested into the annular space between the supersonically spinning disk and the outer edge of the casing. When the flow of air enters this space, the raised sections of the disk rim create a "ramming" effect, generating shock waves and air compression in a manner completely analogous to ramjet inlets on supersonic aerospace vehicles. The efficiency of this compression process is very high because the compressor has very few aerodynamic leading edges, and minimal drag.

  • Un-Shrouded Rotor – Axial Discharge
  • Rotor Flow Path:
     -3 Supersonic Compression Inlet Flow Paths On Disk   Rim
     -High Efficiency, Compact Compression
     -Minimal Number of Leading Edges
     -Flow Path Geometry Similar For Different Pressure   Ratios
  • Combination of Supersonic Flight Inlet & Conventional Axial Flow Compressor Aerodynamics:
     -Rotor Rim Radius Change Produces Compression
     -3 “Blades” (Strakes) Do Minimal Flow Work
     -Axial Inflow/Outflow

Ramgen Air Compressor Rotor Disk

The disk chambers or "strakes" are angled, so the compressed air is "augured" via rotation into a collector and then on to the compressed air system. The compression process is inherently oil-free, requiring no oil for lubrication and/or sealing.

The shock effect begins at the speed of sound. The higher Mach number the greater the shock. The strength of the shock is dependent on the disc speed and the particular gas properties ingested into the Rampressor. The formula for the speed of sound is as follows:

As can be seen, sonic velocity is inversely proportional to the square root of the mole weight of the gas. A heavier gas will have a lower Mach number, or sonic velocity, and conversely, a lighter gas will have a higher Mach number. This is an important consideration in accommodating changes in ambient inlet temperature and matching various gas compression applications. The molecular weights of selected gases are as follows:

Gas Molecular Weight Mach 1 (ft/sec)
Hydrogen 2.0 4290
Methane 16.0 1440
Ammonia 17.0 1410
Water (water vapor or steam) 18.0 1400
Air 28.9 1130
CO2 44.0 880
R410a 72.6 700
R22 86.5 600
R134a 102.0 550
R12 120.9 490
R245fa 134.1 530
R123 152.9 440

The strength of the shock wave, hence the amount of compression, increases exponentially with the Mach number. For example, in air at Mach 1.6 a compression ratio of 3.5:1 is achieved, while at Mach 2.4 it is approximately 15:1. The higher Mach number is achieved by spinning the disc faster.

 

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