ALOBAID, BAKONG, BRUNO
In this paper there will be discussion of the main causes of loss of available energy in a turbo-pump and how those losses can be minimized. Also, the typical turbo-pump efficiencies will be identified. With some help from my group members I was able to point out some discrepancies and better categorize the energy associated with turbopumps and turbomachines. I was told to include diagrams and images to help better illustrate my findings, which I did. Also, I included references as advised. Turbomachines, usually used in mechanical engineering are used to transfer or extract energy from a rotor to a fluid1. In chemical engineering, these machines could be used in chemical plants to transfer energy to fluids being reacted. The process of moving the liquid from a low level to a high level will increase the energy of the liquid after it leaves the pump. A turbo-pump is a gas turbine that has two main components. The rotodynamic pump is one component, being made of several wheels and then there is a driving turbine, usually both are mounted on the same shaft and often geared together. There are also different types of turbo pumps; centrifugal and axial2.
Most turbo-pumps are centrifugal which means the fluid enters the pump near the axis and the rotor accelerates the fluid1. The fluid then passes through a diffuser so that dynamic pressure, also identified as fluid kinetic energy, can be recovered. The diffuser turns the high kinetic energy into high pressures. A portion of the energy goes into kinetic energy of the fluid motion, and some into potential energy, represented by fluid pressure or by lifting the fluid to a higher altitude. The fluid pressure is a result of the rotor and diffuser.
In centrifugal turbines the flow is perpendicular and the energy can be lost by friction in the rotating channels1. Energy loss can also be labeled as power loss. With the rotation movement energy is used to circulate the blades, this causes energy to be lost from the fluid. Other ways centrifugal turbines can lose energy is due to possible shocks against the edges of the blades, due to a boundary layer separation, or due to the development of the boundary layer on the sidewalls of the channels4. Like in some airplanes the propellers or in this case the blades are sometimes damaged by overuse. When blades deform or bend the efficiency of the equipment is not always maximized. The blades in a turbopump are designed to perform to the highest efficiency possible while still producing elevated energy absorbed fluid. That being said, it is relevant to continue observing the blades in a turbopump throughout the lifetime of the machine. Lubrication of the system is also key to maintaining efficiency. Turbopumps must be greased and be able to function consecutively in the same direction, gears could wear down and lubrication helps with reduction of energy losses resulting in an efficient machine3.
Shear force and roughness also have a part in energy efficiency.