Single integral gear

Figure 4-36. A single integral gear box connects one or more expanders to several compressor stages. (Source GHH-Borsig.)...

Figure 12-39C. Single-stage gas compressor with integrally geared drive shaft. (Used by permission Bui. 1.10, Jan 1994. Sunstrand Compressors, Sunstrand Fluid Handling.)...

Turbo compressors can be of the radial or the axial type. They differ from each other in the direction by which the compressed gas leaves the impeller. If the amount of process air is below about 400 000 m h , radial turbo compressors are preferably applied in two particular designs, i.e. the integrally geared turbo compressor and the single-shaft compressor with integrated cooling devices. Their development has decisively pushed the evolution of industrial air separation. The specific thermodynamic and mechanical properties of these compressors will be introduced in the following. 

Another possibility would be to use a multirate code which integrates each differential equation individually using different step sizes. Orailoglu (16) and Gear (17) discuss this approach but their procedure uses multistep Jacobian methods which are not efficient for our system of equations. What we need is a fixed order single step multirate method. 

The interaction of a single molecule with molecules whose oxygen atoms are outside the cutoff sphere are not calculated directly from Eq. (1), but by means of Ewald sum for Coulomb interactions. The equations of motion are integrated with a Gear prediction-correction algorithm at the sixth order. During the initial equilibration time, velocities are scaled every ten steps in order to fulfil the relation ... 

Such a set of equations could be integrated by means of Runge-Kutta routines, were it not that with the elementary step and Single Event Kinetics approach described in Chapter 1, it becomes extremely stiff because of the orders of magnitude difference between the concentrations of molecular and radical species. The Gear routine [1971] was developed to cope with such problems. 

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