Applied Mathematics Seminar September 8th 2005

Date: Thursday September 8th
Time: 11am
Room: RC-4082

The Bernoulli Effect for a compressible gas shows there will be a
drop in pressure, temperature and density when the gas speed increases
isentropically in the narrowing section of a duct. For saturated moist air,
the temperature drop can lead to rapid condensation of microscopic water
droplets and release of latent heat. If the droplets are collected and
thereby prevented from re-evaporation, we find that when the flow has slowed
down isentropically at the duct outlet, the pressure of the energised flow
will be - in theory - greater than the inlet pressure. Surplus pressure can
be used to drive a turbine for electrical or mechanical power.

The lecture will present mathematical models for the proposed motor. The
models will include a one-dimensional cross-sectionally averaged
thermodynamic model to predict theoretical power output and efficiency,
diffusion models for droplet growth and latent heat release, and estimates
for dimensions of the device.

In theory, the motor will deliver power (electrical or mechanical) and
chilled distilled water as co-products. In the real world, feasibility of
the motor is far from certain; triumph of utility over futility will require
brilliant engineering to overcome numerous practical difficulties, as well
as inspired design based on extensive Computational Fluid Dynamics
simulations. The lecture will finish with a description of CFD work in
progress.