A flat surface is made up of electrically heated strips of length 1m and width 0.05m. The strips, which are electrically insulated from one another, are laid with their long sides in contact and an airstream at 25°C flows over the surface in a direction normal to long sides of the strips at a velocity of 65 m/s. Electrical power is supplied individually to each of the strips such that they all have a surface temperature of 229°C. Determine which strip requires the most power. At 400 K, k = 0.0331 W/m·K, ν = 2.610-5 m2·s, ρ = 0.883 kg/m3, Cp = 1013 J/kg·K, Pr = 0.709.

(c) A 50 mm-diameter propeller was installed in a 150 mm-diameter water pipe and the propeller speed was measured for a range of water discharge in the pipe. The water had a density and dynamic viscosity of 1000 kg/m³ and 0.00112 Ns/m² respectively. The measured results were as follows:

Plot the dependence of propeller coefficient against propeller Reynolds number. A geometrically similar propeller with diameter 100 mm was installed in a 300 mm-diameter pipe conveying oil with density 800 kg/m³ and dynamic viscosity 0.007 Ns/m² . Estimate the discharge in the oil pipe for measured propeller speeds of 40 rps and 90 rps.

Producers of metal powders started producing special metal powders for the powder-bed fusion method (such as SLS) of additive manufacturing. Manufacturing companies are advised not to use conventional metal powders for additive manufacturing. Using rational analysis, explain why.

An electrical resistance heater embedded in thin walled tube provides 71 kW of uniform heating to increase the water temperature from 25°C to 75°C. Water enters the circular section of diameter 101 in cm, at a velocity 101 in cm/s. Heat loss to the surroundings is perfectly stopped by an insulation on the outer surface of the heater hence, all the heat dissipated by the heater is transferred to the flowing water in the tube. By analyzing the internal flow convection heat transfer and determine the length of the tube and the surface temperature at the exit of tube? The properties of water at the bulk mean temperature are ?= 1000 kg/m3, Cp= 4100 J/kg-K, k=0.631 W/m-K, Pr= 4.32, ?=0.658×10-6 m2/s.

Q4. (a) Oil with density 870 kg/m3 is conveyed through a pipe at a discharge of 0.11 m3 /s. At a certain location the pipe bends downwards in the vertical plane through an angle of 30 degrees. The pipe has diameter 311 mm at the bend inlet and 211 mm at the bend outlet, and the outlet is 2.5 m below the inlet. The volume of oil contained in the bend is 0.25 m3 . Draw a clearly-labelled definition sketch for the problem. If the gauge pressure at the bend inlet is 200 kPa, calculate the gauge pressure at the outlet and the fluid force on the bend. Assume no losses in the bend.

Saturated water at 20 C flows inside the annular region formed by two concentric circular tubes. The OD=71 in mm, while the ID= 101 mm, The mass flow rate is 0.02 kg/s. , The outer surface is insulated, and the inner surface is kept at 71 C, . Determine the heat transfer coefficient from inner surface to water   under fully developed velocity and temperature flow conditions. Use the following constant thermo-physical properties of water, ρ = 1000kg/m3; μ = 1×10-5 kg/m-s; k = 0.027 W/m-°C; Cp = 4000 J/kg-°C

ROUND UP TO 4 DECIMAL PLACES. Draw and label the P-V & T-S diagrams.

An Ideal air standard dual-combustion cycle has a compression ratio of 15. At the start of the compression process, the air temperature and pressure are 30°C and 150kPa respectively. Heat addition takes place until the maximum cycle temperature reaches 1950°C and produces total heat of 1200 kJ/kg. Determine (a) Temperature, specific volume and Pressure at each state, (b) Net work output (kJ/kg), and (c) thermal efficiency. (d) cut off ratio. (e) mean effective pressure (kPa)

Only 50% of the irradiation on the human skin are absorbed that fall in the range of ?1=0.71 ?? to ?2=1.71 ?? .Radiation with shorter wavelengths than ?1 and longer wavelengths than ?2 are completely absorbed. Assuming the solar surface to be a black surface of temperature 5527C, calculate the fraction of solar irradiation absorbed by the human skin?

Suppose you have a 4340 steel plate in fully reversed axial loading, with an axial load varying from 15000 lbf to -15000 lbf. The plate is 1⁄4” thick, 2” high, and 5” long. A hole is in the center of the plate, and is 1/4“ in diameter. The stress concentration factor chart is in the Quiz 3 References. The fully adjusted endurance limit was found to be Se = 25 ksi.​

The fatigue strength fraction f is 0.76. The notch sensitivity is 0.95.

What is the life in cycles of this bar?

References Fully Reversed Loading Fatigue:

https://d3c33hcgiwev3.cloudfront.net/_b812cd169fbe57b00756e256731aa4a3_Quiz-3--References-Fully-Reversed-Loading-Fatigue-.pdf?Expires=1593993600&Signature=c5lXDSj-l8Sa7aUp1pCxY88L-MSbdEMoEUYl-YZMNvdU11UqQ-2vZAPYcuzbYmwZt28RMIoSf~KHf-5h6nZgUc89eqWDtLRmffjmk1wjAgll8Vgnuhza-m3ni5~IjL9utiaQrGCmoFZBEr8FzNyHi1629kpKoMAL4FHW7TRLG5g_&Key-Pair-Id=APKAJLTNE6QMUY6HBC5A

Explain the phenomena of creep and stress rapture

A fuel mixture consists of 90% octane (C₈H₁₈) and 10% ethyl alcohol (C₂H₅OH), by volume. This fuel mixture is burned with 200% theoretical dry air in a combustion chamber at atmospheric pressure.

a) Write the balanced reaction equation for complete combustion of this fuel mixture.

b) Determine the theoretical air-fuel ratio.

c) Actual air-flow rate for a fuel mixture flow rate of 5 kg/s.

d) Calculate the molar mass of the mixture product gases.

can someone explain teardown analysis and competitive benchmarking with examples, please?

A water pump has the following performance based on the tabulation below: Q, liters/min Total head, m Power in, W 100 12.0 208.5 120 10.0 204.2 140 8.5 211.3 160 7.5 227.9 180 7.0 263.8

1. Make computations each for the efficiencies at the different flowrates and total heads of the pump. Recommend at what total head should the pump be operated for maximum efficiency.