Thrust control

Thrust-bearing-load meters for protection against excessive loading are available on thrust bearings, and automatic thrust control, which functions by controlling the pressure behind a balancing drum, also is available. 

Positive-lock thrust control for precision rotor and shaft positioning to maintain original performance and minimize wear for extended pump life. 

Hybrids is the name given in rocket technology to systems in which a solid fuel in the form of a case-bonded charge with a central perforation is reacted with a liquid oxidant. Hybrids with solid oxidant and liquid fuel also exist. Hybrids can be thrust-controlled during combustion and can even be re-ignited if hypergolic components are incorporated in the formulation of the fuel charge. 

FADEC systems govern the thrust control of engines. Therefore, the certification requirements for the application of TLD to FADEC systems require that the Loss of Thrust Control (LOTC) rates related to those systems must meet certain requirements. There are two basic requirements. The first of these is that the average system LOTC rate must not exceed 10 failures per 10 flight hours. This limit was established since this... 

El-Hawary, K, ed. 2001. Ocean Engineering Handbook. Boca Raton, IT. CRC Press. Geared primarily to electrical engineers, also covered are topics such as vehicle control and positioning and thrust control systems, both relevant to mechanical engineering. 

This part considers reactive power control with the use of shunt and series capacitors. The controls may be manual or automatic through electromagnetic or static devices. Protection of capacitors and capacitor banks as well as design, manufacturing and test requirements, installation and maintenance are also covered, the main thrust being on the application of power capacitors. 

Centrifugal (radial inflow) turboexpanders are well adapted to such energy conservation schemes and, with recent developments that have increased their reliability, are suitable for unattended service on a 24-hour, 7-day week operational basis. Some of the recent developments include better shaft seals, thrust bearing monitoring, and superior control devices. 

In this automatic thrust balancing system, the pressure behind the compressor wheel is controlled to a value between the compressor suction pressure and the wheel peripheral pressure. As the expander inlet pressure increases above the compressor suction pressure level, the resulting thrust force pushes the compressor wheel, and hence the rotor system, towards the compressor suction. In the reverse situation, when the pressure behind the compressor wheel is reduced below the wheel peripheral pressure level, the rotor system moves toward the expander. 

The modified Brayton cycle is used for both gas turbines and jet engines. The turbine is designed to produce a usable torque at the output shaft, while the jet engine allows most of the hot gases to expand into the atmosphere, producing usable thrust. Emissions from both turbines and jets are similar, as are their control methods. The emissions are primarily unbumed hydrocarbons, unbumed carbon which results in the visible exhaust, and oxides of nitrogen. Control of the unbumed hydrocarbons and the unburned... 

It is desirable to have additional axial-load control on the multistage compressor. A balance piston, also refeired to as the balance drum, can be located at the discharge end (see Figure 5-46). The balance piston consists of a rotating element that has a specified diameter and an extended rim for sealing. The area adjacent to the balance piston (opposite the last stage location) is vented, normally to suction pressure. The differential pressure across the balance piston acts on the balance piston area to develop a thrust force opposite that generated by the impellers. The pressure on the... 

At present, the principal thrust of shock-induced solid state chemistry rests upon preservation of samples that have been subjected to controlled, quantitative, reproducible shock loading. Such an endeavor must, of necessity, involve close, cooperative efforts between materials communities, including solid state physics, materials science, and shock-compression science. 

Waterjets have been developed for application to high-speed ships. The waterjet has an inlet usually on the side or bottom of the ship in the region of the stern, which allows water to flow into a water pump. The pressure of the water is raised in the pump, and the water is expelled as a jet to produce the desired thrust. The direction of the jet flow can be controlled to provide maneuvering forces, eliminating the need for rudders. The propulsive coefficient of modern... 

Bit Pressure Loss. It is necessary to choose the bit pressure loss such that the thrust load created in combination with the weight on bit will yield an on-bottom load on the motor thrust bearings, which is less than the maximum allowable load for the bearings. Since this is a deviation control run and, therefore, the motor will be drilling only a relatively short time and distance, the motor thrust bearings will be operated at their maximum rated load for on-bottom operation. Figure 4-206 shows that maximum allowable motor thrust bearing load is about... 

---