Molecular Physics | Thermodynamics Answers

An oil- fired boiler takes in feed water at 75°C and produces wet steam at a pressure of 5 bars. The steam flow rate 1.50 tons/hr with a dryness fraction of 0.89. The fuel consumption rate is 6.10kg/min and its net calorific value is 41MJ/Kg. Determine the thermal efficiency of the boiler.

A sample of wet steam is passed through a simple throttling calorimeter. The steam entry pressure recorded on a gauge is 9 bar. Immediately after throttling, the temperature is 110 °C, where the steam is at atmospheric pressure of 1 bar. Calculate the dryness fraction of the steam sample.

A steam turbine is supplied with superheated steam at a pressure of 20 bar and a temperature of 350 °C. The steam exhausts to a condenser at a pressure of 0.1 bar and dryness fraction of 0.85. If the steam flow rate is 2 tonnes per hour and the power output is 420 kW, calculate the thermal efficiency of the energy conversion process.

A boiler takes in feed water at 70 °C and generates steam at a pressure of 10 bar and dryness fraction of 0.92. The wet steam enters a superheater and emerges with the same pressure at a temperature of 400 °C. If the steam flow rate is 5 tonnes per hour, determine (i) the rate at which heat transfer takes place in the boiler and (ii) the rate at which heat transfer takes place in the superheater.

How much heat is needed to turn the 1 kg of ice at -4°C to turn it into vapor at 100°C?

Two litres of hydrogen at a pressure of 10^5 Pa expands adiabatically to 1.5 times the initial volume. Find the work done?

A centrifugal compressor which represents an open system takes in air at a pressure
of 2 bar and a temperature of 28 °C at the rate of 1. 4 m 3 s −1. Compression takes
place according to the law PV 1.3 = C and the delivery pressure is 3.5 bar. The characteristic gas constant for the mixture is 287 J kg −1 K −1 and its specific heat
capacity at constant pressure is 1005 J kg −1 K −1 Determine:
(i) the input power and (ii) the heat transfer rate.

I kg of a fluid expands reversibly according to a linear law from 4.2 bar to 1.4 bar; the initia] and final volumes are 0.004 m) and 0.02 m). The fluid is then cooled reversibly at constant pressure, and finally compressed reversibly according to a law po = constant back to the initial conditions of 4.2 bar and 0.004 m '. Calculate the work done in each process and the net work of the cycle. Sketch the cycle on a. p-v diagram,

A centrifugal compressor which represents an open system takes in air at a pressure of 2 bar and a temperature of 28 c at the rate of 1.4 m/s. compression takes place according to the law PV
^1.3 =C and the delivery pressure is 3.5 bar Determine (i) the input power and (ii) the heat transfer rate.

Evaluate and compare the work and heat transfer when 0.8kg of air, at a pressure of 2.6 Bar and a temperature of C degree, expand in a closed thermodynamic system to three times its initial volume : (1) according to ti Boyles law and, (2) according to Charles law. The characteristic gas constant for air is 200 J kg -1 K-1 and its specific heat capacity at constant volume is 700Jkg -1 K-1