Shaft power

The use of wind as a renewable energy source involves the conversion of power contained in moving air masses to rotating shaft power. These air masses represent the complex circulation of winds near the surface of Earth caused by Earth s rotation and by convective heating from the sun. The actual conversion process utilizes basic aerodynamic forces, ie, lift or drag, to produce a net positive torque on a rotating shaft, resulting in the production of mechanical power, which can then be used directly or converted to electrical power. 

The gas turbine power plant which has revolutioni2ed aviation derives basically from the steam turbine adapted to a different working fluid. The difference is cmcial with respect to fuel because steam can be generated by any heat source, whereas the gas turbine requires a fuel that efficiently produces a very hot gas stream and is also compatible with the turbine itself. The hot gas stream results from converting chemical energy in fuel directly and continuously by combustion in compressed air. It is expanded in a turbine to produce useful work in the form of jet thmst or shaft power. 

C 3d virial coefficient. kPa- kPa- vi< Shaft power for flow process Btu/s... 

Belt selection depends on power and development of the required tensile strength. Knowing drive-shaft power, belt tension can be calculated and a belt selected. However, since various combinations of width and ply thickness will develop the required strength, final selection is influenced by lump size, troughability of the belt, and abihty of the belt to support the load between idlers. Thus it is necessaiy to use an empirical approach to arrive at a belt selection which meets all requirements. 

The common indices of the physical environment are temperature, pressure, shaft power input, impeller speed, foam level, gas flow rate, liquid feed rates, broth viscosity, turbidity, pH, oxidation-reduction potential, dissolved oxygen, and exit gas concentrations. A wide variety of chemical assays can be performed product concentration, nutrient concentration, and product precursor concentration are important. Indices of respiration were mentioned with regard to oxygen transfer and are particularly useful in tracking fermentation behavior. Computer control schemes for fermentation can focus on high productiv-... 

To calculate the specific speed, N, it is necessary to select a reasonable shaft speed. First, calculate the approximate shaft power by assuming... 

Expander performance will shift as plant conditions—such as gas flowrate, gas inlet, and discharge pressure—gas composition, and inlet temperature change. Calculation of expander diermal efficiency from field data is not accurate because expander discharge flow normally consists of two phases, gas and liquid. Efficiency calculations should always be cross-checked with the shaft power produced before any decision on expander performance is made. 

An expander performanee map of shaft power versus mass flow with lines of eonstant inlet temperature and pressure shall be provided. There shall be a minimum of four eonstant pressure lines with inerements of approximately 5 psi and a minimum of four eonstant temperature lines with inerements of approximately 100°F. The map shall be valid for rated speed with normal exhaust pressure and gas eomposition. The normal operating point shall be indieated on the map. 

A hot gas expander is typieaiiy deseribed by a map of shaft power versus mass flowrate (Figure 7-3). Notiee that there are four parameters ehanging in this partieuiar map w, J, Pj, and Tj. Figure 7-3 is most useful when the family of eurves (whieh are for a eonstant rotational speed) reduees to a single eurve in a two-dimensional spaee. Usually, expander eharaeteristies are a very weak funetion of angular speed. However, in eases where the variations due to rotational speed are important, a third dimension is required. This dimension should be equivalent speed, Ng. 

Input shaft power is the head of the compressor multiplied by the weight flow and divided by an appropriate efficiency with the result... 

A typical value for the temperature rise efficiency is. 9. For shaft power, W5,... 

Step 5. Solve for the shaft power substituting into Equation 4.7. 

Step 5. For the final step, compute the new shaft power value u ig ion 4.7. 

The following equation provides a way of estimating the dischaige temperature if the shaft power is known, or it can be used to estimate the shaft power if the temperature rise and quantity of lubricant is known. The equation assumes 85% of the heat of the compressor is absorbed by the lubricant. 

Step 15. To complete the estimate, calculate the shaft power, using the conversion of 33,000 ft-lb/min/hp. 

Mechanical losses shall not exceed 10% of the total shaft power input at test conditions. 

One of the critical measurements is torque or shaft power. A variety of methods is recognized direct methods such as torque meters or reaction mounted drivers (dynamometers) and indirect methods such as electrical power input to drive motors, heat balance, or heat input to a loop cooler. See Part 7, Measurement of Shaft Power, PTC 19.7 1961 [3] for additional information. 

Shaft power increases as the fan approaches the maximum volume. 

Shaft power increases as fan approaches maximum volume, unlike the backw ard-curved fan, w here it decreases. 

For isentropic or nonisentropic flow, the fan shaft power is greater than the power required for the flow through the impeller. 

A proportion of the shaft power is used to overcome the bearing friction. This is allowed by using the mechanical efficiency. Thus, the required axial power is... 

If the rotational velocity change is within reasonable limits and chauical efficiency does not change, Eqs. (9.74), (9.112) and (9.115) shaft power relation as... 

The fan is tested at an air pressure of 102.9 kPa, temperature of 10 °C, and a rotational speed of 970 rev min T Under these conditions the volume flow is 0.7 m s S total pressure difference is 250 kPa, and shaft power is 250 kW. If the operating conditions change to handle an air temperature of 14 °C and pressure of 100 kPa and the efficiency remains unchanged, calculate under the new operating conditions the volume flow, total pressure difference, and shaft power. 

The duct pressure drop is 589 Pa airflow is 1944 L s" Determine the fan total pressure, volume flow, shaft power, and total efficiency. 

A fan delivers air Co a ventilating system at total pressure difference 500 Pa, The fan is running at 10 rev s, and the shaft power needed in these conditions is 7.46 kW. Determine the volume flow, total pressure difference, and shaft power if the fan speed is increased to 12.5 rev... 

Reversing the process yields an efficient method of energy storage. The process inputs combustion products such as carbon dioxide and water, and energy in tlie form of electricity or shaft power, and outputs oxygen and fuel (typically hydrogen or hydrocarbons). 

PrImary-Voltage-Control-AC Motor Driver. Induction motor torque at any slip s is proportional to primary V. Rotor-power dissipation is equal to s times the air-gap power. These two relationships define the boundary of operation of an induction motor with primary voltage control of speed. As the speed is reduced (s increased) at constant torque, the air-gap power remains fixed, but the power divides between rotor circuit dissipation and mechanical shaft power. 

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