18. A centrifugal air compressor compresses air at the rate of 20 kg/min from 1 bar to 2 bar. The temperature increases from 20°C to 120°C during the compression. Determine actual and minimum power required to run the compressor. The surrounding air temperature is 20°C. Neglect the heat interaction between the compressor and surroundings and changes in potential and kinetic energy. (Ans. 24.2 kW)

18. A centrifugal air compressor compresses air at the rate of 20 kg/min from 1 bar to 2 bar. The temperature increases from 20°C to 120°C during the compression. Determine actual and minimum power required to run the compressor. The surrounding air temperature is 20°C. Neglect the heat interaction between the compressor and surroundings and changes in potential and kinetic energy. (Ans. 24.2 kW)

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

A turbine is driven by a system that enters the turbine at the ff. conditions: 200 kg/h, 39 atm, 501 deg C, 49 m/s linear speed. The steam exits at a point 8 meters below the inlet stream of the turbine with the following conditions: atmospheric pressure, 290 m/s speed. 69000 W of shft work is delivered by the turbine while 100 kcal/h heat is lost. What is the value of (a) expansion work and (b) flow work? If the value is zero, explain why is it so.If it cannot be calculated, explain why.
In a steam turbine system, suppose the value of ∆mH is constant (meaning, inlet and outlet conditions are maintained). From the energy balance equation, Qnet + Wnet = ∆mH + ∆KE + ∆PE or −0.1209 kW − 70 kW = ??̇? + 8.75 kW − 0.0068kW 1. What will happen to Wnet if there was no increase in kinetic energy, will the magnitude of Wnet increase or decrease? What should be the sign of potential energy so that Wnet will increase in magnitude?2. For a turbine system, what should happen to Qnet, ∆KE, and ∆PE to maximize the work done by the turbine? Which factor is the most significant?
With a flow rate of 50 kmol/hour, air is compressed from P 1 = 1.2 bar pressure to P 2 = 6 bar pressure. The power required for this process is 98.8 kW. Temperature and speed data are given below. T1 = 300 K ,T 2 = 520 K ,v1 = 10 m/s, v2 = 3.5 m/s What is the heat rate transferred to the compressor (kJ/s)? Assume that air has Cp = (7/2)R and enthalpy is independent of pressure. (Gpt/Ai wrong ans not allowed)
Energy balance results (in kW) obtained for the same medium speed single cylinder diesel engine are reported in the following table. For case 1, if the coolant temperature is 105 °C at the outlet of the engine and the volumetric flow rate is 0.22*10-3 m3/s, the temperature of the coolant at the inlet is (in °C): (The coolant is considered water with a density 999 kg/m3 and a specific heat 4.2 k/kg.K). Case N (rpm) bmep (bar) W. O ambient Q ahast shaft 2.2 4.2 19.1 60.3 9.90 3.52 1 500 7.1 24.5 23.8 500 6.1 3.6 5.2 400 3.50 4.9 4.1 1.4 Select one: O a. 142.1 O b. 112.7 O c. 97.31 O d. 87.2 O e. 370.31
A two stage compressor with first stage piston displacement of 94,390 cu.m/sec is driven by a motor. Motor output is 35 HP, suction temperature 22 degC, volumetric efficiency is 85%, mechanical efficiency is 95%, the intercooler pressure is 30 psi gage. Air temperature in and out of the intercooler are 105deg C and 44 degC, respectively. Final discharge pressure is 100 psi gage, while suctionis estimated to be 14.4 psi. Determine the compression efficiency.
Identify what is the system in this problem and write the general energy balance equation (no need to solve) A turbine is driven by a system that enters the turbine at the ff. conditions: 200 kg/h, 39 atm, 501 deg C, 49 m/s linear speed. The steam exits at a point 8 meters below the inlet stream of the turbine with the following conditions: atmospheric pressure, 290 m/s speed. 69000 W of shft work is delivered by the turbine while 100 kcal/h heat is lost. What is the specific delta H?
15 - A fixed volume insulated tank, initially empty, was connected to a distribution line carrying helium gas at a temperature of 135ºC by means of a valve. The valve is opened first and closed when the pressure is the same as the distribution line pressure. What is the final internal energy of helium in the tank? (Internal energy of the warehouse in the final state = Enthalpy of the distribution line). (Cp=5.1926) will be taken. a) 701.0 kJ/kg B) 597.1 kJ/kg NS) 2014.7 kJ/kg D) 2066.7 kJ/kg TO) 2118.6 kJ/kg
Air flows steadily through an engine at constant temperature, 127 deg C. Assuming that the Kinetic and Potential energies are negligible and if the exit pressure is one-fourth of the initial pressure, in which the initial pressure is 702 kPa, the work per mass is Answer kJ (nearest whole number).
P23. Steam enters an insulated nozzle with negligible velocity, 200 psi and 500°F. Steam exits at 100 psi and 400°F.For steady-state operation and neglecting potential energy effects, determine the velocity of the steamleaving the nozzle in ft/s.
4. A 14 x 12-in., single-cylinder, double-acting air compressor with 5.5% clearance operates at 12 rpm. The suction pressure and temperature are 14 psia and 100°F, respectively. The discharge pressure is 42 psia. Compression and expansion processes are polytropic, with n= 1.30. Determine (a) the volumetric efficiency, (b) mass and volume at suction conditions handled each minute, (c) the work, (d) the heat rejected, (e) the indicated air hp developed if the polytropic compression efficiency is 75%, and (f) the compression efficiency. Answer: (a) 92.7% (b) 247.8 cfm, 16.72 lb/min (c) -18.93 hp (d) -175.7 Btu/min (e) -25.24 hp (f) 77.42%
The following parameters are recorded on a gas turbine test rig. Stage-1: Inlet temperature is 5000C, Inlet pressure is 650kPa. Exit gas pressure 150kPa. Determine the exit gas temperature for isentropic process. Stage-2 Gas is again heated to 4500C by constant volume process. Assume R=287 J/kg.K; Determine the heat added to the gas assuming Cp/Cv=1.4 and Cp/Cv=1.3; Draw the T-S diagram for the above process.
a SSSF control volume has three inflow streams, where each inflow stream has a mass-flow-rate, m(dot) = 2kg/sec. In addition, there are two outflow streams, where one of these outflow streams has a mass-flow-rate, m(dot) = 5 kg/sec. What is the mass flow rate of the second outflow stream in kg/sec?