21. A horizontal pipe delivers steam at 1 MPa and a rate of 100 kg/s to a steam turbine. The pipe (O.D. = 11.5 cm and I.D. = 96.5 cm) is made of carbon steel. You may assume that the air and the walls of the turbine building are both at 20 C. Use an emissivity of 0.81 for the pipe surface to estimate the rate of heat loss, per unit length of the pipe, due to the free convection and thermal radiation mecha- nisms.

21. A horizontal pipe delivers steam at 1 MPa and a rate of 100 kg/s to a steam turbine. The pipe (O.D. = 11.5 cm and I.D. = 96.5 cm) is made of carbon steel. You may assume that the air and the walls of the turbine building are both at 20 C. Use an emissivity of 0.81 for the pipe surface to estimate the rate of heat loss, per unit length of the pipe, due to the free convection and thermal radiation mecha- nisms.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter5: Analysis Of Convection Heat Transfer

Section: Chapter Questions

Problem 5.12P

See similar textbooks

Similar questions

HANDWRITTEN AND FINAL ANSWER MUST BE IN ENGLISH UNITS. Show solution. An experimental gas turbine engine is under development to increase its mechanical efficiency. It has a turbine efficiency of 95% and compressor efficiency of 85%. The following parameters are provided: P1 = 550 kPa, T1 = 25 deg C, rp = 5.5, T3 = 1450 deg C, Wnet = 5500 kW. Compute for the (a) flow rate and (b) mean effective pressure. Consider Ethane as your working fluid.
Catalogue data of a water-cooled condenser of a manufacturer gives the following details: Condensing temperature 48.9°C Water inlet temperature 37.8°C Water flow rate 20.694 kg/s Capacity 145 tons Estimate the capacity of this condenser with the same water flow rate but with an inlet temperature of 30°C and a condensation temperature of 42°C. The evaporation temperature may be assumed to be constant at 2.2°C.
A boiler plant incorporates and economizer and air preheater and generates steam at 40 bar and 300oC with fuel heating value of 33000 kg/hr. The temperature of feedwater is raised from 40oC to 125oC in the economizer and the flue gases are cooled at the same time from 395oC to 225oC. The flue gas then enters the air preheater at a pressure of 1.2 bar and 16oC with a pressure rise across the fan of 18 mm of water. The power input to the fan is 5 kW and it has mechanical efficiency of 78%. Neglecting heat losses and assuming the flue gases as ideal gas with constant specific heat of Cp = 1.01 kJ/kg-K, calculate: (a) the mass flow rate of the air, (b) the temperature of flue gases leaving the plant, (c) the mass flow rate of the steam, and (d) the efficiency of the boiler.
A steam condenser receives 10 kg per second of steam with an enthalpy of 2570 KJ/kg. Steam condenses into liquid and leaves with an enthalpy of 160 KJ/kg, if cooling water passes through the condenser with temperature increases from 13oC to 24oC. Calculate the cooling water flow rate in kg/sec. Show conversion of units pls
1.1 Determine the electrical power supplied to a boiler when the temperature of the enteringwater is 20 C and the exiting temperature is 89 C. The flow of.the pressured water is 2 Kg/s. There is anegligible pressure drop through this boiler and it operates at a constant pressure of 3 bars. The specificheat is c = 4,370 J/(Kg K). There is a 1.5(105) W rate of heat loss from the boiler during this process to asurrounding at 293.2 k. Consider steady state conditions.1.2 Calculate the total rate of entropy production in Problem 1.1.1.3 Calculate the total rate of exergy destruction (W) in Problem 1.1. The dead statetemperature is 293.2 K and pressure is 1 bar.1.4 Calculate the mass flowrate of fuel (natural gas, CH4) required to heat the water flow to theconditions of problem 1.1 if the electrical heating device is replaced with a gas fired boiler. The highheating value (HHV) of the fuel is 50.02 MJ/kg.1.5 Calculate the exergy destroyed in the process described by problem 1.4. The exergy…
1.1 Determine the electrical power supplied to a boiler when the temperature of the enteringwater is 20 C and the exiting temperature is 89 C. The flow of.the pressured water is 2 Kg/s. There is anegligible pressure drop through this boiler and it operates at a constant pressure of 3 bars. The specificheat is c = 4,370 J/(Kg K). There is a 1.5(105) W rate of heat loss from the boiler during this process to asurrounding at 293.2 k. Consider steady state conditions.1.2 Calculate the total rate of entropy production in Problem 1.1.1.3 Calculate the total rate of exergy destruction (W) in Problem 1.1. The dead statetemperature is 293.2 K and pressure is 1 bar.1.4 Calculate the mass flowrate of fuel (natural gas, CH4) required to heat the water flow to theconditions of problem 1.1 if the electrical heating device is replaced with a gas fired boiler. The highheating value (HHV) of the fuel is 50.02 MJ/kg.1.5 Calculate the exergy destroyed in the process described by problem 1.4. The exergy…
Steam enters the condenser of a steam power plant at a flow rate of 18000 kg/h, a degree of dryness of 0.86 and a pressure of 15 kPa, leaving the condenser as a saturated liquid at the same pressure.A nearby river water is used for the cooling of the condenser.Calculate the water flow rate of the cooler if the water of the river can be heated up to 10°C in order to avoid thermal pollution. (Cp,su=4,18 kj/kgK) (Note: the potential energy change is negligible.)
An air-cooled condenser has an h value of 30 W/m2-K based on the air-side area. The air-side heat transfer area is 190 m2 with air entering at 27°C and leaving at 40°C. If the condensing temperature is constant at 49°C, what is the air mass flow rate in kg/s? Let Cp(air) = 1.006 kJ/kg-K. Draw and label the temperature-flow diagram. Round off your answer to three (3) decimal places.
What is the engine bore (in mm) required for good volumetric efficiency for an engine with two inlet and two exhaust valves, stroke of 90 mm, inlet air temperature of 332 K, exhaust temperature of 900 K, engine speed of 8200 rpm and exhaust valve diameter 22 mm (each). Assume specific heat ratio =1.3, R = 287 J/kg.K, and an average inlet flow coefficient 0.4 and an average exhaust flow coefficient 0.5. Select one: O a. 96.57 O b. 70.23 O c. 105.2 O d. 91.05 O e. 82.71
A ramjet drives a missile at V0=966m/s at an altitude of 33.5km (air density 0.01kg/m3 and T0=232K). If the missile inlet captures a stream tube of air A0=1,1m2 in area, the fuel-to-air ratio is 0,049, and the fuel heating value is 50MJ/kg. if the ramjet engine produces net thrust Fn= 8,9 kN , What is the useful power that the engine introduces to the missile?
please solve it i need urgent A naturally-aspirated (NA) oil engine (i.e., a slow-speed CI Engine) which produces one power pulse in two revolutions of its crankshaft is to be designed to operate with the following characteristic at sea level where the mean atmospheric conditions are Pa = 101325 N/m2 and ta = 17°C. The value of gas constant of air is Ra = 0.287 kJ/(kg·K). Gross brake power, Wb, gross = 300 kW Volumetric efficiency, hvol = 80% Brake specific fuel consumption, sfcb = 255 g/(kW·h) Actual air-to-fuel ratio, (A/F)act = (m a / m f )act = 17:1 Angular speed of the shaft, w = 125 rad/s Calculate: (i) The required engine capacity Vs, total in cc (cm3), as well as in litres (L); Vs is the swept volume, and (ii) the brake mean effective pressure ( Pbm ). The engine is fitted with a supercharger (SC) so that it may be operated at an al- titude, z, of 3000 m (above sea level) where the atmospheric pressure (Pa) in N/m2 is determined from the following relation: Pa =…
Consider a CI engine with a fuel injector mounted at the center of the cylinder head. The bore of the engine is 10 cm. The injector has a nozzle diameter of 0.05 mm and a discharge coefficient of 0.65. The fuel injection pressure is 600 bar. If the average cylinder pressure during injection is 50 bar and the density of the fuel is 800 kg/m3, estimate the time for a fuel particle to reach the cylinder wall.