Turbomachinery embraces a number of devices that are classified as 'open', such as propellers, windmills and unshrouded fans. The machines examined here are those defined as 'closed', where a finite quantity of fluid can be considered to pass through the machine in unit time, for it is these which are of the most interest to students and professionals in the fields of mechanical, chemical, and plant engineering. It is in these areas that the devices that form the subject matter of this book find their most important applications, making this treatment of vital importance to anyone working in or studying them.