L5 slide 5: Throttling valve (ENGR5003)

L5 slide 5: Throttling valveFrom lectureCurrent specThird1 marks2 min

ENGR5003 Lecture 5, slide 5 (Q1 - Throttling process)

A gas flows steadily through a throttling valve. The valve is well insulated, and changes in kinetic and potential energy are negligible. Which statement is correct?

Formulas you may need

SFEE: $q - w = (h_2 - h_1) + \tfrac12(C_2^2 - C_1^2) + g(Z_2 - Z_1)$ (on the formula sheet)
Throttling: $h_1 = h_2$ (learn this)

AThe temperature must remain constant.BThe pressure remains constant while enthalpy decreases.CThe enthalpy remains approximately constant across the valve.DThe internal energy must remain constant.