Air is flowing through a thick walled copper pipe that can be considered to be isothermal at 450 degrees C. Inner diameter of the pipe is 3cm and 0.9m long. Air enters at 30 degrees C and exit bulk temperature is 95 degrees C. if the length is now doubled assuming air mass flow rate and heat transfer coefficient remain the same in both lengths what is the new bulk temperature at the exit? a) 148.58°C b) 151°C c) 140.2°C d) 158.6°C

Air is flowing through a thick walled copper pipe that can be considered to be isothermal at 450 degrees C. Inner diameter of the pipe is 3cm and 0.9m long. Air enters at 30 degrees C and exit bulk temperature is 95 degrees C. if the length is now doubled assuming air mass flow rate and heat transfer coefficient remain the same in both lengths what is the new bulk temperature at the exit? a) 148.58°C b) 151°C c) 140.2°C d) 158.6°C

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

Differantial Equations
Engineering economics Investing in Electrical Efficiency Two pumps capable of delivering 100 hp to an agricultural application are being evaluated in a present economy study. The selected pump will only be utilized for one year, and it will have no market value at the end of the year. Pertinent data are summarized as follows: ABC Pump XYZ PumpPurchase price $2,900 $6,200Maintenance cost $170 $510Efficiency 80% 90% If electric power costs $0.10 per kWh and the pump will be operated 4,000 hours per year, which pump should be chosen? Recall that 1 hp = 0.746 kW. Choose XYZ because it provides least cost.
Dusty air at a fertilizer plant flows through a 13% efficient cyclone and then through an ESP, The inlet air to the cyclone has a dust loading of 80 grains/cubic foot. In order to meet a standard of 98,5% collection efficiency for the fertilizer plant as a whole, what is the allowable concentration of dust (in grains/cubie foot) in the air that exits from the ESP?a. 0.15 gr/ft3 b 1.2 gr/ft3c. 21.6 gr/ft3 d. 58.4 gr/ft3
A wind turbine has the maximum power output at the rated speed of 12 m/s and a rotor diameter of 82 meters. The cut-in and cut-out speeds for this type of wind turbine are 4 m/s and 23 m/s, respectively. The table below shows the annual wind data near a potential site for setting up a wind farm using this type of wind turbine and the power coefficient of the wind turbine at the specific wind speed. The air density is 1.22 kg/m3. (a). What is the maximum power output of this wind turbine, assuming Betz limit? (b). What is the average power output if the wind turbine is installed at this site?. (c). What is the capacity factor of the wind turbine at this site? (d). If a wind farm consisting of 100 such wind turbines is built at the site, how much energy does this wind farm generate in a year (in the unit of kWh)? (e). Is this a good site for using this particular type of wind turbine?
In the United States, energy for household heating is generally sold using English units, e.g., therm, gal, and cord. A house in Wisconsin uses 1200 therms of thermal energy during the heating season. Calculate the cost of fuel if the furnace uses (a) natural gas with an efficiency of 70%; (b) No. 2 fuel oil, efficiency 65%; (c) kerosene, efficiency 99.9% (unvented); and (d) wood with l5% moisture with an efficiency of 50%. Use the data in Tables 2.2, 2.7, and 2.13. The efficiencies are based on the HHV. Assume the cost of natural gas is $8/MBtu, the cost of No. 2 fuel oil is $3/gal, the cost of kerosene is $3.50/gal, and the cost of wood is $100/cord. Assume the bulk density of cord wood is 30 lbm/ft3 .
PROPAGATION OF ERROR You are tasked to supervise the design of 0.5MW wind turbine to be constructed in a Wind Farm in Pililla, Rizal. Suppose the design criteria are as follows: The air density as surveyed after 2 year period averaged at 1.225 kg / cubic meter. The sweeping diameter of the rotor blades is 125m, and the anemometer reading in the area amounts to 4.2m/s on a 2 year period of survey. if the diameter measurement is off by 0.1m and the anemometer reading is also fluctuating by 0.05m/s. In the design specifications given, if the actual measurement of power via the substation amounts to exactly 530kW and given that the windspeed is off by 0.05m/s, what could have been the error in the measurement of diameter? Your answer must be in 3 decimal places and in correct signs and measurement. Show complete solution in paper.
7. Two parallel plates separated by 15.5 cm move with a relative velocity of 7 m/s. How much force per unit area is required to maintain the velocity difference if the fluid separating the plates is (a) water with µ = 1 cP (b) SAE 30 motor oil with µ = 200 cP and (c) honey with µ = 10,000 cP?
Suppose we got the following data during a test of a 2- stroke engine in which gas is usedas a fuel:Diameter of the piston = 149 mmStroke length = 179 mmClearance volume = 0.88 literrpm of the engine = 302Indicated mean effective pressure = 6.0 barGas consumption = 6.0 m3/hCalorific value of the gas (fuel) = 16990 kJ/m3Make a clear sketch the geometry of this engine using the data and determine thefollowing:i. Indicated power developed by the engine in watt.ii. Air Standard Efficiencyiii. Indicated thermal efficiency of the engine.
(04) A thin fat plate ( 45 cm X 90 cm ) is immersed in a stream of glycerin Tp= 1258 kg/m° and u = 1.49 Pa.s) with a velocity of (7 m/s ). Compute the skin frictional (viscous ) drag exerted on the upper surface of the plate, if : a) The plate side parallel to the stream is the shortest side b) The plate side parallel to the stream is the longest side You may use the following relations: CDIam = 1.328 / ReL 1/2 Cpturb = 0.072 / ReL 1/5
PROPAGATION OF ERROR You are tasked to supervise the design of 0.5MW wind turbine to be constructed in a Wind Farm in Pililla, Rizal. Suppose the design criteria are as follows: The air density as surveyed after 2 year period averaged at 1.225 kg / cubic meter. The sweeping diameter of the rotor blades is 125m, and the anemometer reading in the area amounts to 4.2m/s on a 2 year period of survey. What is the theoretical power output of the turbine assuming 100% efficiency of operation? Your answer must be in kW and in two decimal places with correct signs. In the previous problem, if the diameter measurement is off by 0.1m and the anemometer reading is also fluctuating by 0.05m/s and if the error measurement for theoretical power output must be limited to 3%, WHY OR WHY NOT should you accept the design? * Show complete solution in paper.
Flow is driven along a long, straight, circular pipe by a pressure drop. On investigating a portion of this pipe, far from the inlet and outlet sections and with a steady state flow, we observe a pressure drop of Δp=10 Pa across a length of the pipe L=8.6 m. The radius of the pipe is R=0.2 m. The fluid properties are as follows: the dynamic viscosity is μ=0.05 m2 s-1 and density is ρ=1000 kg m-3. Find the Reynolds number based on the diameter of the pipe, evaluated at the middle of the pipe section. Give your answer to two decimal places. please stop copy from internet, there are a lot of wrong solutions. To give you a hint the final answer is 930 but i need a detailed solution. thank you
MECHANICAL ENGINEERING UPVOTE WILL BE GIVEN. PLEASE WRITE THE COMPLETE SOLUTIONS LEGIBLY. SHOW THE STEP-BY-STEP PROCESS WITH SHORT COMMENT/EXPLANATION. ANSWER IN 4 DECIMAL PLACES. Two gaseous streams containing the same fluid enters a mixing chamber and leaves as a single stream. For the first gas the entrance conditions are A1=500 cm², v1=230 m/s, p1=1.60 kg/m³. For the second gas the entrance conditions are A2= 300 cm³, m2=8.84 kg/s, v2=0.502 m³/kg. The exit stream conditions is v3=130 m/s and v3=0.437 m3/kg. Determine the following: (a) the total mass flow leaving the chamber (kg/sec) (b) the velocity of the gas at 2. (m/sec)