O air enters a pipe at 25 °C, 100 kPa with a volumetric flow rate of 23 m/h. On the outer pipe surface is an electrical resistor covered with insulation. With a voltage of 120 V, the resistor draws a current of 4 amps. Assuming the ideal gas model with c, = 1.005 kJ/kg - K for air and ignoring kinetic and potential energy effects, determine i. the mass flow rate of the air, in kg/h ii. the temperature of the air at the exit, in °C

O air enters a pipe at 25 °C, 100 kPa with a volumetric flow rate of 23 m/h. On the outer pipe surface is an electrical resistor covered with insulation. With a voltage of 120 V, the resistor draws a current of 4 amps. Assuming the ideal gas model with c, = 1.005 kJ/kg - K for air and ignoring kinetic and potential energy effects, determine i. the mass flow rate of the air, in kg/h ii. the temperature of the air at the exit, in °C

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

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Where necessary, assume air as an ideal gas and consider R = 287 J/(kg.K), Cp = 1005 J/(kg.K), Cv = 718 J/(kg.K). a) A nozzle is a device that is used to increase the velocity of a fluid by varying the cross-sectional area. At the last section of a jet engine (Fig Q1.a, section 5), air with a mass flow rate of 50 kg/s at a pressure of 500 kPa and a temperature of 600 K enters a nozzle with an inlet cross-sectional area of 5 m2. The exit area of the nozzle is 20% of its inlet area. The air leaves the nozzle at a velocity of 300 m/s. The nozzle is not well-insulated and during this process, 5 kJ/kg heat is lost.Figure Q1.a: Schematic of a Jet engine.(iii) Calculate the density of the air as it leaves the nozzle.
Where necessary, assume air as an ideal gas and consider R = 287 J/(kg.K), Cp = 1005 J/(kg.K), Cv = 718 J/(kg.K). a) A nozzle is a device that is used to increase the velocity of a fluid by varying the cross-sectional area. At the last section of a jet engine (Fig Q1.a, section 5), air with a mass flow rate of 50 kg/s at a pressure of 500 kPa and a temperature of 600 K enters a nozzle with an inlet cross-sectional area of 5 m2. The exit area of the nozzle is 20% of its inlet area. The air leaves the nozzle at a velocity of 300 m/s. The nozzle is not well-insulated and during this process, 5 kJ/kg heat is lost. Figure Q1.a: Schematic of a Jet engine.(ii) Determine the density and velocity of the air entering thenozzle.
Where necessary, assume air as an ideal gas and consider R = 287 J/(kg.K), Cp = 1005 J/(kg.K), Cv = 718 J/(kg.K). a) A nozzle is a device that is used to increase the velocity of a fluid by varying the cross-sectional area. At the last section of a jet engine (Fig Q1.a, section 5), air with a mass flow rate of 50 kg/s at a pressure of 500 kPa and a temperature of 600 K enters a nozzle with an inlet cross-sectional area of 5 m2. The exit area of the nozzle is 20% of its inlet area. The air leaves the nozzle at a velocity of 300 m/s. The nozzle is not well-insulated and during this process, 5 kJ/kg heat is lost.Figure Q1.a: Schematic of a Jet engine. (i) In analysing this nozzle using the 1st law of thermodynamics, the change in which type of energy is negligible?
1. Where necessary, assume air as an ideal gas and consider R = 287 J/(kg.K), Cp = 1005 J/(kg.K), Cv = 718 J/(kg.K). a) A nozzle is a device that is used to increase the velocity of a fluid by varying the cross-sectional area. At the last section of a jet engine (Fig Q1.a, section 5), air with a mass flow rate of 50 kg/s at a pressure of 500 kPa and a temperature of 600 K enters a nozzle with an inlet cross-sectional area of 5 m2. The exit area of the nozzle is 20% of its inlet area. The air leaves the nozzle at a velocity of 300 m/s. The nozzle is not well-insulated and during this process, 5 kJ/kg heat is lost.Figure Q1.a: Schematic of a Jet engine.(iv) Determine the temperature of the air as it leaves the nozzle.
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