Water enters at 115 ℃ at a rate of 2 kg/s in a double-pipe parallel flow heat exchanger to heat a chemical whose inlet temperature is 20 ℃ and at a rate of 3 kg/s. The overall heat transfer coefficient of the heat exchanger is 1200 W/m2. ℃. The heat transfer surface area of the heat exchanger is 7.8 m2. What is the actual heat transfer rate of the heat exchanger? The specific heats of the water and chemical are given to be 4.18 and 1.8 kJ/kg.℃, respectively.

Water enters at 115 ℃ at a rate of 2 kg/s in a double-pipe parallel flow heat exchanger to heat a chemical whose inlet temperature is 20 ℃ and at a rate of 3 kg/s. The overall heat transfer coefficient of the heat exchanger is 1200 W/m2. ℃. The heat transfer surface area of the heat exchanger is 7.8 m2. What is the actual heat transfer rate of the heat exchanger? The specific heats of the water and chemical are given to be 4.18 and 1.8 kJ/kg.℃, respectively.

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.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.49P

See similar textbooks

Similar questions

In a single-body, four-pipe transition heat exchanger, the hot combustion product gases are cooled by water. Flow of gases 3 kg / s, specific temperature0.95 kJ / kg.°C; water flow 0.2 kg / s, specific temperature 4.2 kJ / kg.°C dir. The total heat transfer coefficient of the heat exchanger is 300 W / m2.K, heat transfer surface area is 10 m2.a) the heat transfer that occurs and the output temperatures of both fluids;b) find the logarithmic mean temperature difference.
A gas turbine exhaust stack cooler drops the gas temperature from 1020oF to 605°Fby means of a water cooling coil. Cooling water enters the coil at 65°F and leaves,after a counter-flow passage, with a temperature of 190°F. If cp for the gas is 0.26Btu/lb.F, calculate the overall heat transfer coefficient for an exchanger area of2000 ft2, Btu/hr.ft2.F.A. 19.94 B. 29.94 C. 39.94 D. 49.94
9.) Milk at 40 ° C with a specific heat of 3.85 kj / kg K will be pasteurized at 75 ° C by using saturated steam at 120 ° C in a plate heat exchanger. The heat exchanger operates in parallel flow. What is the milk rate? The data required for steam is given in the table below. Enthalpy (MJ / kg) Temperature (°C) Absolute pressure (kpa) Saturated liquid Evaporation Saturated Steam 75 38.5575 0.31394 2.3214 2.6354 120 198.54 0.50372 2.20225 2.70607 A.)0.017 B.)56.33 C.)68.7 D.)0.056 E.)17.75
Cold water (cp = 4180 J/kg·K) enters the tubes of a heat exchanger with 2-shell passes and 12-tube passes at 14°C at a rate of 3 kg/s, while hot oil (cp = 2200 J/kg·K) enters the shell at 200°C at the same mass flow rate. The overall heat transfer coefficient based on the outer surface of the tube is 300 W/m2·K and the heat transfer surface area on that side is 20 m2. Determine the rate of heat transfer using (a) the LMTD method and (b) the ε–NTU method
C). Hot chemical products ( Cph = 2.5 kJ/kg.K ) at 600 0C and at a flow rate of 30 kg/s are used to heat cold chemical products ( Cp = 4.2 kJ/kg.K ) at 200 0C and at a flow rate 20 kg/s in a parallel flow heat exchanger. The total heat transfer is 50 m2 and the overall heat transfer coefficient may be taken as 1500 W/m2.K Calculate the outlet temperatures of the hot and cold chemical products.
Hot exhaust gases of a stationary diesel engine are to be used to generate steam in an evaporator. Exhaust gases (cp = 1051 J/kg·K) enter the heat exchanger at 550°C at a rate of 0.25 kg/s while water enters as saturated liquid and evaporates at 200°C (hfg = 1941 kJ/kg). The heat transfer surface area of the heat exchanger based on water side is 0.5 m2 and overall heat transfer coefficient is 1780 W/m2·K. Determine the rate of heat transfer, the exit temperature of exhaust gases, and the rate of evaporation of water.
3. In a shell-and-tube heat exchanger, water enters at 85°C at the rate of 5.4 kg/s. Engine oil enters at 20°C and leaves at 60°C. The water leaves the heat exchanger at 57°C. What is the mass flow rate of the engine oil? Express your answer in kg/s.
A thin-walled, double-tube, counterflow heat exchanger is used to cool oil (Cp = 2.20 kJ/kg °C) from 150 to 40°C at a rate of 2 kg/s by means of water (Cp = 4.18 kJ/ kg °C), which enters at 22°C at a rate of 1.5 kg/s. Determine the rate of heat transfer in the exchanger and the leaving temperature of the water.
An aircraft air conditioner is to be optimized to achieve minimum first cost. During the day the temperature of air in the ACM is reduced to 800 degrees K from Tmax. The net heat transfer of the ACM is _____kJ. The density of air is 1.29 kg/m3, and its specific heat is 1.005 kJ/(kg*K). The cost of the primary heat exchanger in dollars is 38.5V, where V is the volume in cubic inches and the cost of the ACM in dollars is 125.3A, where A is the area in squared inches. Using A and V as the variables, set up the objective function and constraint to optimize the first cost. Set it up so that there is one constraint equation.
A cross-flow air-to-water heat exchanger with an effectiveness of 0.65 is used to heat water (cp = 4180 J/kg·K) with hot air (cp = 1010 J/kg·K). Water enters the heat exchanger at 20°C at a rate of 4 kg/s, while air enters at 100°C at a rate of 9 kg/s. If the overall heat transfer coefficient based on the water side is 260 W/m2·K, determine the heat transfer surface area of the heat exchanger on the water side. Assume both fluids are unmixed.
A counter-flow heat exchanger is used to cool oil (cp = 2.20 kJ/kg⋅ºC) from 110ºC to 85ºC at a rate of 0.75 kg/s by cold water (cp = 4.18 kJ/kg⋅ºC) that enters the heat exchanger at 20ºC at a rate of 0.6 kg/s. If the overall heat transfer coefficient is 800 W/m2⋅ºC, the heat transfer area of the heat exchanger is a. 0.760 m2 b. 0.790 m2 c. 0.805 m2 d. 0.745 m2 e. 0.775 m
10. In a double-pipe counterflow heat exchanger, water at the rate of 60 kg/min is heated from 65 oC to 95 oC by an oil having a specific heat of 0.36 J/kg oC. The oil enters the exchanger at 200 oC and leaves at 140 oC. Determine the heat exchanger area for an overall heat transfer coefficient of 50 J/m2. oC.hr given Cp of water as 1 J/kg oC?