2-3. Temperature Drop in a Throttling Valve and Energy Balance. Steam is flowing through an adiabatic throttling valve (no heat loss or external work). Steam enters point 1 upstream of the valve at 689kPa abs and 171.1C, and leaves the valve (point 2) at 359kPa. Calculate the temperature t2 at the outlet. [Hint: Use Eq. (4.2-21) for the energy balance and neglect the kinetic-energy and potential-energy terms as shown in Example 4.2-1. Obtain the enthalpy H1 from the steam tables in Appendix A.2. For H2, linear interpolation of the values in the table will have to be done to obtain H=4.57m. Use SI units. Ans. t2=160.6C