7. It is required to transport a hydrocarbon as a two-phase mixture of liquid and vapour along a smooth-walled pipe with an inside diam- eter of 100 mm. The total hydrocarbon flow rate is 2.4 kgs-1 with a vapour mass fraction of 0.085. The pipe is to operate at an absolute pressure of 2.2 bar. The liquid density is 720 kgm³, and viscosity is 4.8 × 10-4 Nsm 2, while for the vapour, the density is 1.63 kgm³, and the viscosity is 2.7 x 10-5 Nsm-2. Determine the maximum per- missible length of pipe if the pressure drop along the pipe is not to exceed 20 kNm-2. Answer: 44 m