Mechanical Engineering Answers

Estimate the heat transfer rate on a rice hull furnace wall 

1 m x 1 m 1x 1m outside dimension. The inside temperature 

of the furnace is 800℃ while the outside is 28 ℃. the furnace 

insulation is 0.19 m thick red brick with heat conductibility of 

0.74 Kcal/hr-m- ℃. also compute the percentage heat loss 

of the furnace assuming it consumes rice hull ay a rate of 15 

kg/hr (3000 Kcal/kg). Neglect heat losses at the corner and 

edges of the furnace. Tfurnace wall = 800 ℃

The angular acceleration 𝛼, rad/s2 of a rotating disk is related to its angular velocity 𝜔, rad/s by 𝛼 = 4 √𝜔. When t = 0, the disk is at rest and the angular position coordinate of a line in the disk is θ = 8rad. Find the expression for θ(𝜔).

A two-stage, double-acting compressor is to deliver 90 lb/min of air from 14.3 psia and 90 ̊F to a final pressure of 185 psia. The normal barometer is 29.8 in. Hg and the temperature are 80 ̊F. The pressure drop in the intercooler is 3 psi and the temperature of the air at the exit of the intercooler is 90 ̊F, the speed is 210 remand pV1.34 =C during compression and expansion. The clearance is 5% for both cylinder. The temperature of the cooling water increases by 18 ̊F. Find: a) The volume of free air b) The discharge pressure of the low-pressure cylinder for minimum work, c) The temperature at discharge from both low pressure and high-pressure cylinders d) The mass of cooling water to be circulated about each cylinder and through the intercooler e) The work f) If, for the low-pressure cylinder, L/D = 0.68 and if both cylinders have the same stroke, what should be the cylinder dimensions?

A fluid at 0.7bar occupying 0.09m^3 is compressed reversibly to the pressure of 3.5bar according to the law pv^n=C. The fluid is heated reversibly at constant volume until the pressure is 4bar, the specific volume is then o.5m^3/kg. A reversible expansion according to the law pv^2=C restores the fluid to its initial state. Sketch the graph and calculate the mass of the fluid present, the value of the n in the first process, and the network of the cycle.

A fuel contains by mass 88% C,H, 8% ash (silica). Calculate the stoichometric air

A heatpump is to be used to heat a building during the winter. The building is estimated to be looosing heat at a rate of 136000kj/hr when the outside temperature drops to 5°c. Determine the minimum power required to drive the heatpump unit for this outside temperature

A heat engine has a combustion chamber where 450KW of heat is generated every second. Out of this, 55% is successful transferred to the boiler fluid while the rest is lost in tbe exhaust of the heat added in the boiler, 140KW is converted to work in the turbine while the turbine supplies 55KW to the pump. Determine the efficiency of the heat engine

A carnot heat pump is to be used to heat a house and maintain it at 20°c in winter. On a day when the average outdoor temperature remains at about 2°c. The house is estimated to loose heat at a rate of 82000kj/hr. If the heatpump consumes 8KW of electricity while operating l, determine how long the pump ran on that day

Consider the actual powerplants operating with solar energy. Energy is supplied to one plant from a solar pond at 80°c and to the other from concentrating collectors that raise the water temperatures to 600°c. Which of these powerplants will have a higer efficiency? Explain