Question

Water is the working fluid in an ideal Rankine cycle. Saturated vapor enters the turbine at 12 MPa, and the condenser pressure is 8 kPa. The mass flow rate of steam entering the turbine is 50 kg/s. Determine the percent thermal efficiency.

Answer 1

Without enthalpy values or temperature details, we cannot calculate the exact percent thermal efficiency for the ideal Rankine cycle. Efficiency is generally calculated as the ratio of the net work output to the heat input, using specific enthalpy values from steam tables.

Step-by-step explanation:

To determine the percent thermal efficiency of the ideal Rankine cycle, we can use the 1st law of thermodynamics and properties of steam.

The thermal efficiency (η) for a cycle is defined by the ratio of the net work output of the system to the heat input.

We can calculate the net work output by subtracting the work output by the turbine (Wt) from the work input to the pump (Wp).

However, the question does not provide the specific enthalpies needed to calculate Wt and Wp, nor does it provide the temperatures required to calculate efficiency using the Carnot cycle equation.

Typically, the Enthalpy of the steam at turbine inlet and outlet conditions, along with the enthalpy of the feedwater at the pump inlet, are necessary to calculate Wt and Wp.

With turbine inlet pressure at 12 MPa and condenser pressure at 8 kPa, these values would be looked up in steam tables.

The heat input (Qh) is usually the heat added in the boiler, which is the difference in enthalpy between the turbine inlet and the feedwater inlet.