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The power needed to overcome wind and friction dragassociated with an automobile traveling at a constantvelocity of
(a) Determine the required heat transfer area of theradiator if the vehicle is equipped with an internalcombustion engine operating at an efficiency of
(b) Determine the required water mass flow rate andheat transfer area of the radiator if the vehicle isequipped with a fuel cell operating at
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- Hello! I'd like help with the following exercise, from Levenspiel's "Engineering Flow and Heat Exchange". Leftover air at 20ºC and 100kPa is driven by a fan through a horizontal galvanized conduit of 1 m in diameter and 10m in length at a speed of 10 m/s. What size motor should be used if its efficiency is 90% and that of the fan is 20%? I'm not sure where to start. My professor hasn't explained much about this subject.arrow_forwardA counterflow heat exchanger is employed to cool 0.55 kg/s (CP = 2.45 kJ/kg-K) of oil from 115°C to 40°C by the use of water. The inlet and outlet temperatures of cooling water are 15°C and 75°C, respectively. The overall heat transfer coefficient is expected to be 1450 W/m2-°C. Using the NTU method, calculate the following:a. The mass flow rate of water.b. The effectiveness of the heat exchanger c.Surface area requiredarrow_forwardA Counter-flow heat exchanger (water-to-water) with these specifications. Hot water enters at 95 oC while cold water enters at 20 oC. The exit temperature of hot water is 15 oC greater than that of cold water, and the mass flow rate of hot water is 50 percent greater than that of cold water. The product of heat transfer surface area and the overall heat transfer coefficient is 1400 W/K. Taking the specific heat of both cold and hot water to be Cp = 4180 J/kg.K, Calculate: (a) The outlet temperature of the cold water, (b) LMTD (c) The effectiveness of the heat exchanger, (d) The mass flow rate of the cold water, (e) The heat transfer rate.arrow_forward
- Water (cp = 4182 J/Kg.K) at a flow rate of 5000 Kg/hr is heated from 10oC to 35oC in an oil cooler by engine oil (cp = 2072 J/Kg.K) with an inlet temperatureof 85oC and a flow rate of 6000 Kg/hr. Take the overall heat transfer coefficient to be 3500 W/m2.K. What are the areas required for:a. Parallel Flow.b. Counter Flowarrow_forwardEstimate the annual operating cost for a heat pump that delivers 30,000 BTU per hour of heat during winter and a similar rate of cooling during summer. Assume the heat pump operates 8 hours per day for 120 days in summer, and 12 hours per day for 120 days in winter. The Seasonal Energy Efficiency Ratio (SEER) for summer cooling is 16 BTU/Wh, and the Heating Season Performance Factor (HSPF) for winter heating is 12 BTU/Wh. The cost of electricity is $0.20/kWh.arrow_forwardA company owns a refrigeration system whoserefrigeration capacity is 200 tons (1 ton of refrigeration =211 kJ/min), and you are to design a forced-air cooling systemfor fruits whose diameters do not exceed 7 cm under the followingconditions:The fruits are to be cooled from 28°C to an average temperatureof 8°C. The air temperature is to remain above -2°Cand below 10°C at all times, and the velocity of air approachingthe fruits must remain under 2 m/s. The cooling section canbe as wide as 3.5 m and as high as 2 m.Assuming reasonable values for the average fruit density,specific heat, and porosity (the fraction of air volume in a box), recommend reasonable values for the quantities related to the thermal aspects of the forced-air cooling, including (a) how long the fruits need to remain in the cooling section, (b) the length of the cooling section, (c) the air velocity approaching the cooling section, (d) the product cooling capacity of the system, in kg fruit/h, (e) the volume flow rate…arrow_forward
- A steam power plant is located in the northern part of the country. Steam in the plant flows steadily through a 0.17-m diameter pipeline from the steam generating unit (SGU) to the steam turbine. At the SGU end, the steam conditions are determined to be P = 4 MPa, t = 400°C, h = 3,247 kJ/kg, and specific volume = 0.181 m³/kg. At the steam turbine end, the conditions are found to be P = 3.5 MPa, t = 392°C, h = 3,178.3 kJ kg, and specific volume = 0.248 m³/kg. Heat loss from the pipeline is 7.86 kJ/kg. Determine the steam mass flow rate in kg/s.arrow_forwardThe overall engine heat transfer coefficient (W/m2.K) for a single cylinder engine with a 0.09 m bore and stroke, average combustion gas temperature of 995 K, coolant temperature of 355 K, and fuel-air flow rate of 1.8 *10-2 kg/s is: (Assume the thermal conductivity is 0.062 W/m.K and the dynamic viscosity is 19*10-6 N.s/m2). Select one: O a. 4240 O b. 8924 O c. 8320 O d. 7238 O e. 5630arrow_forwardA steam power plant is equipped with a condenser that removes 300 MW of heat from steam condensing at 30°C. The tubes of the heat exchanger have an internal diameter of 2 cm, and the overall heat transfer coefficient is 3500 W/m² °C. The cooling is provided by cooling water from a surrounding river, which enters the tubes at 18°C and leaves at 26°C. Determine the heat transfer surface area in m². (A) 19, 600 B 20, 600 11, 770 D) 18, 600arrow_forward
- i need the answer quicklyarrow_forwardParvinbhaiarrow_forwardIn an heat exchanger of parallel flow type, water enters at 60°C and leaves at 80°C while oil of specific gravity 0.8 enters at 250°C and leaves at 100°C. The specific heat of oil is 2.5 kJ/kg K and surrounding temperature is 300 K. Determine the loss in availability on the basis of one kg of oil flow per second.arrow_forward
- Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning