Mechanical Engineering Answers

If the pressure in container A in Fig. P2.38 is 150 kPa,

compute the pressure in container B.

We are running out of resources. What practical ways would you recommend for packaging milk and other canned foods

A boiler produces 6 tonnes/hour of steam at a pressure of 1.8 MPa and a temperature of 250ºC. Feedwater enters at a temperature of 39ºC. At exit from the economizer part of the boiler the temperature is 72ºC. At exit from the evaporator part of the boiler the steam is 90 % dry. Energy is supplied by 650 kg of coal per hour, which has a calorific value of 36 MJ/kg. The A/F ratio is 25 : 1. The temperature of the flue gas at entry to the economizer part of the boiler is 430ºC. The average specific heat at constant pressure of the flue gas in the economizer is 1045 J/kg.K. 4.1 Calculate the efficiency of the boiler. 

What is the temperature of 2 liters of water at 30°C after 3,500 calories of heat have been added?Use: Cp=4.187 KJ/Kg.-°K, 1 Kg. = 1 liter, 1 Kcal = 4.18 KJ

During a test on a boiler the following data were recorded: Pressure = 1.7 MPa Steam temperature at exit = 240ºC Steam flow rate = 5.4 tonnes/hour Fuel consumption = 400 kg/hour Lower calorific value of fuel = 40 MJ/kg Temperature of feedwater = 38ºC Specific heat capacity of superheated steam = 2100 J/kg.K Specific heat capacity of liquid water = 4200 J/kg.K. Calculate: 5.1 Efficiency of the boiler. 5.2 Equivalent evaporation (EE) of the boiler [91 %; 16.1] 

A boiler produces 6 tonnes/hour of steam at a pressure of 1.8 MPa and a temperature of 250ºC. Feedwater enters at a temperature of 39ºC. At exit from the economizer part of the boiler the temperature is 72ºC. At exit from the evaporator part of the boiler the steam is 90 % dry. Energy is supplied by 650 kg of coal per hour, which has a calorific value of 36 MJ/kg. The A/F ratio is 25 : 1. The temperature of the flue gas at entry to the economizer part of the boiler is 430ºC. The average specific heat at constant pressure of the flue gas in the economizer is 1045 J/kg.K. 4.1 Calculate the efficiency of the boiler. [70.5 %] 4.2 Draw up an energy balance, on a kJ/kg coal basis, with percentages of the total energy supplied. [economizer 3.6 %, evaporator 59 %, superheater 8 %, other 29.4 %] 

A vibration damper unit is composed of a rubber cylinder of diameter d compressed inside of a wrought-iron cylinder by a force F applied to the steel rod. Develop, in terms of d, F, and Poisson’s ratio ν for the rubber, the following expression for the lateral pressure p between the rubber and the wrought-iron cylinder. Compute the value of 𝑝 for the following data:

𝑑 = 63.5 𝑚𝑚, 𝜈 =0.5, 𝑎𝑛𝑑 𝐹 = 9 𝑘𝑁.

9. Water enters the cooling tower at 55oC and leaves at 30oC while the heat rejected to air is 120 KW. Find the capacity of the pump needed to pump the water.

Find the horizontal and vertical force per foot of width on the tainter gate shown in figure below which has y = 62.4 C 25-1t radius Water C 25ft 36

If the pressure in container A in Fig. given below is 150 kPa, compute the pressure in container Wider 18 cm Oil, 16 cm 22 cm Mercury 8 cm