A turbopump is a pump designed to increase the pressure of a liquid or gas with the goal of increasing engine power or performance. Applications for these pumps include car, rocket and high-powered vehicle engines. Most turbopumps include some kind of rotodynamic pump combined with a driving turbine. Almost all turbopumps are built with a centrifugal or axial flow design. Despite the many potential uses, they are often considered challenging to design, and loss of some efficiency is considered common.
Though the specific inner workings of a turbopump depend on the application and design, the basic goal is the same. Gas or fluid is pumped into a chamber, where it is forced to a higher pressure by blades rotating along an axis. Many times the pumps are designed with specific shapes to encourage increased pressure and delivery of that pressurized material to a specific location. Pressurized fuel, for instance, can be delivered into some engines to increase the efficiency of combustion inside the engine.
There generally are two major designs used to create turbopumps. Most often, a turbopump will be based on the concept of a centrifugal pump. In these, liquid is injected along an axis, and the spinning rotors force the material to the edges of a progressively widening diffuser. These designs can often produce the highest pressures because of the relatively unrestricted flow of materials through the diffuser. As a result, a centrifugal pump might be seen most often in vehicles requiring a great deal of power, such as rockets and tanks.
An axial flow pump, on the other hand, usually produces lower pressure with greater efficiency. Fluid is still released at one end of a chamber, usually along an axis. The difference is that the rotating blades physically push the material toward a specified location rather than relying on centrifugal forces. Often combined with other pumps, an axial flow pump is considered easier to design and utilize in machines that do not require large amounts of power or pressurized fuel.
In general, turbopumps can be challenging to design and often operate at reduced efficiencies. Depending on whether a turbopump is centrifugal or axial flow, problems such as recirculation and backward flow can often be expected. Most of these problems involve the fuel or other materials not reaching the desired pressure the first time through the chamber. With car engines and other low-power machines, efficiency loss can be tolerated. In precise machines such as rockets, careful consideration is usually necessary when utilizing turbopump technology.