![]() Is there physical significance in these criteria? In all the analytical and experimental work seen so far, these two criteria have been used. A pertinent question to ask is what criterion is best. We observe that there is a considerable spread in the pressure loss fractions depending on the criterion chosen. When using these criteria, the drill bit nozzles have to be selected to satisfy the fractions defined before. The fractions of pressure drops are then given by Eqs. The following example demonstrates the application of these concepts.Īssume that we consider the hydraulic system used in the previous section. (5.16) and (5.17) define the fraction for parasitic pressure losses that gives the maximum hydraulic horsepower and jet impact beneath the drill bit. ( For a sample output report from a liquid pipeline thermal hydraulics analysis using LIQTHERM software, refer to Appendix A.15. One such software is LIQTHERM developed by SYSTEK Technologies, Inc. Several commercial software packages are available to perform thermal hydraulics. Such a program can subdivide the pipeline into short segments and calculate the temperatures, liquid properties, and pressure drops as we have seen in the examples in this chapter. Thermal hydraulics is very complex and calculations require use of some type of a computer program to generate quick results. ![]() It can be seen from the foregoing that manual calculation of temperatures and pressures along a heated oil pipeline is definitely a laborious process that can be eased using programmable calculators and personal computers. This is left as an exercise for the reader. Calculations are repeated until successive values of T 2 are within close agreement. This value of T 2 is used as a second approximation in Eqn (7.34) to calculate a new value of T m and subsequently the next approximation for T 2. ![]() The electric energy consumption can easily be determined if you know the kW input to the motor. For example, if the BHP calculated for a pump is 245 HP, the electric motor that drives the pump will require a power input of 245/0.95 at 95% motor efficiency. An electric drive motor may have an efficiency of 95%, which can be used to determine the electric power input to the motor, knowing the BHP of the pump. Based on the driver efficiency, its power will be more than the pump power calculated. The driver of the pump, which may be an electric motor, a turbine, or a diesel engine, must provide enough power to the pump. It must be noted that the BHP calculated is the power required by the pump that is transferred as pressure to the liquid pumped. If the pumped liquid is something other than water, the BHP can be calculated by multiplying the WHP by the liquid specific gravity. When water is the pumped liquid, the BHP calculated is called the water horsepower (WHP). Sg: specific gravity of liquid pumped, dimensionlessĮ: pump efficiency (decimal value, less than 1.0)
0 Comments
Leave a Reply. |