Description Efficient  but noisey cleaning of surfaces can be achieved using supersonic nozzles if operated correctly and there are many commercial examples available using CO2 pellets as an erodent. This project investigates their design and operation. This project will also examine available design methods for a variety of nozzle types. The project can be easiliy extended to involve two students who are intersted in the following aspects, gas dynamics, modelling , coding, design  and experimental testing. Key Objectives The main objectives include (i) Developing basic models for nozzle design (ii) Investigating a variety of nozzle shapes (iii) Developing a simple test facility to examine cleaning efficiency