A counter-flow heat exchanger is used to cool water from 60°C to 20°C. The water flows at 0.2 m/s through the inner tube and the cooling fluid flows in the enclosure. The inner tube is 6-cm in diameter and 15-m in length. It is thin and made of copper. The flow rate of the cooling fluid is 1.2 kg/s and convection coefficient is 360 W/m².°c. The specific heat of the cooling fluid is 1600 J/kg. °C. The surface temperature of the inner tube can be approximated as almost isothermal. (a) What is the mass flow rate of water? 0.56 kg/s (b) What is the effectiveness of this heat exchanger? 0.285

A counter-flow heat exchanger is used to cool water from 60°C to 20°C. The water flows at 0.2 m/s through the inner tube and the cooling fluid flows in the enclosure. The inner tube is 6-cm in diameter and 15-m in length. It is thin and made of copper. The flow rate of the cooling fluid is 1.2 kg/s and convection coefficient is 360 W/m².°c. The specific heat of the cooling fluid is 1600 J/kg. °C. The surface temperature of the inner tube can be approximated as almost isothermal. (a) What is the mass flow rate of water? 0.56 kg/s (b) What is the effectiveness of this heat exchanger? 0.285

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 single-pass, cross-flow heat exchanger uses hot exhaust gases (mixed) to heat water (unmixed) from 30 to 70 °C at a rate of 3 kg/s. The exhaust gases, having thermophysical properties similar to air, enter and exit the exchanger at 200 and 100 °C, respectively. If the overall heat transfer coefficient is 200 W/m2 ·K, estimate the required surface area. Hint : from 30 to 70 °C at a rate of 3 kg/s.
In a double-pipe, counter-flow heat exchanger, water entering at 1.5 kg/s is heated from 25°C to 70°C as it flows thru the inner pipe. Hot oil enters the heat exchanger at 2.5 kg/s and 115°C. The convection heat transfer coefficients in the cold- and hot-sides are 100 and 50 kW/m2.°C, respectively. Calculate the required heat transfer area in m2. Take Cp= 4.18 kJ/kg.°C for water, and cp = 1.67 %3D %3D kJ/kg.°C for oil.
Water enters at 20 ℃ at a rate of 0.1 kg/s in a double-pipe counter flow heat exchanger is to be heated by hot air that enters the heat exchanger at 90 ℃ at a rate of 0.3 kg/s. The overall heat transfer coefficient based on the inner side of the tube to be 100 W/m2. ℃. The length of the tube is 14 m and the internal diameter of the tube is 1.4 cm. Determine the outlet temperature of the water. The specific heats of the water and air are given to be 4.18 and 1.01 kJ/kg.℃, respectively.Select one:a. 30.5 ℃b. 24.3 ℃c. 28.8 ℃d. 32.7 ℃
Consider the flow of motor oil (cp=2048 J/kg K) through a copper tube ofthin wall at a rate of 0.3 kg/s. The oil enters the copper tubes at atemperature of 80°C that is cooled by means of water that enters at 20°C. Temperatureoutlet of the oil cannot be higher than 40°C. The convective coefficient ofheat transfer from the oil side is 750W/m2 K and from the water side 350W/m2 K. IfThe outlet temperature of the water is measured at 32°C and a heat exchanger is considered.double tube in parallel. Determine: a) Mass flow rate of the water. b) The difference of log mean temperatures. c) the area of the heat exchanger.
Calculate the liquid flow rate for a heat exchanger with one tube pass. The liquid is heated from 20°C to 93°C by a hot gas at 260°C and 0.45 kg/s. A-4.64 m², U-280 W/m²
Water enters at 20 °C at a rate of 0.1 kg/s in a double-pipe counter flow heat exchanger is to be heated by hot air that enters the heat exchanger at 110 °C at a rate of 0.3 kg/s. The overall heat transfer coefficient based on the inner side of the tube to be 100 W/m2. °C. The length of the tube is 14 m, and the internal diameter of the tube is 1.4 cm. Determine the outlet temperature of the water. The specific heats of the water and air are given to be 4.18 and 1.01 kj/kg.°C, respectively. Select one: O a. 31.3 °C O b. 22.6 °C O C. 24.7 °C O d. 25.5 °C
With reference to the schematic below, a thin-walled double-pipe counter-flow heat exchanger is to be used to cool a hot fluid (cp=2200 J/kg.°C) from 150°C to 50°C at a rate of 2 kg/s by water (cp = 4180 J/kg°C) that enters at 22°C at a rate of 1.5 kg/s. The diameter of the tube is 2.5 cm, and its length is 6 m. Determine the overall heat transfer coefficient, U of this heat exchanger. Hot fluid 150°C Cold water 22°C 150°C Assumptions: 1.Steady operating conditions exist. 2 The heat exchanger is well-insulated so that heat loss to the surroundings is negligible.
Water enters at 20 ℃ at a rate of 0.1 kg/s in a double-pipe counter flow heat exchanger is to be heated by hot air that enters the heat exchanger at 90 ℃ at a rate of 0.3 kg/s. The overall heat transfer coefficient based on the inner side of the tube to be 100 W/m2. ℃. The length of the tube is 14 m and the internal diameter of the tube is 1.4 cm. Determine the outlet temperature of the air. The specific heats of the water and air are given to be 4.18 and 1.01 kJ/kg.℃, respectively. Select one: a. 82.6 ℃ b. 74.7 ℃ c. 72.5 ℃ d. 77.9 ℃
A thin-walled double-pipe counter-flow heat exchanger is to be used to cool oil (Cpo= 2200 J/kg.K) from 150°C to 40°C at a rate of 2 kg/s by water (Cpw= 4180 J/kg.K) that enters at 22°C at a rate of 1.5Kg/s. If the diameter of the tube is 2.5 cm, and its length is 6 m, determine * The rate of heat transfer in the heat exchanger * The outlet temperature of the cold fluid * The Log Mean Temperature Difference (LMTD) * The overall heat transfer coefficient
The oil (cp = 1 795 W-s/kg-K) from an oil-cooled electric transformer is cooled from 79.4 oC to 29.4 oC at the rate of 1 360.5 kg/h. This is done in an oil-water het exchanger that receives 2 948 kg/h of water at 15.6 Celsius. For the exchanger, U = 295 W/m2-K. Find the exit water temperature and heating area required (a) for counter flow and (b) for parallel flow.
A long, thin-walled double-pipe heat exchanger with tube and shell diameters of 0.01 m and 0.025 m, respectively, is used to condense refrigerant-134a with water at 20°C. The refrigerant flows through the tube, with a convection heat transfer coefficient of hi= 4100 W/m² °C. Water flows through the shell at a rate of 0.3 kg/s. The thermal resistance of the inner tube is negligible since the tube material is highly conductive and its thickness is negligible. Both the water and refrigerant-134a flows are fully developed. Properties of the water and refrigerant-134a are constant. Water properties: p = 998 kg/m³, v=u/p-1.004x 10-6 m²/s, k = 0.598 W/m. °C, Pr = 7.01 Cold water D Do
A two-shell passes and four-tube passes heat exchanger is used to heat glycerin from 20°C to 50°C by hot water, which enters the thin-walled 2-cmdiameter tubes at 80°C and leaves at 40°C. The total length of the tubes in the heat exchanger is 60 m. The convection heat transfer coefficient is 25 W/m2∙K on the glycerin (shell) side and 160 W/m2∙K on the water (tube) side. Determine the rate of heat transfer in the heat exchanger (a) before any fouling and (b) after fouling with a fouling factor of 0.0006 m2∙K/W occurs on the outer surfaces of the tubes.