8.9 × 10-4 Nsm-2. Answer: 2.7 kNm²²m-1 4. An experimental test rig is used to examine two-phase flow regimes in horizontal pipelines. A particular experiment involved uses air and water at a temperature of 25°C, which flow through a horizontal glass tube with an internal diameter of 25.4 mm and a length of 40 m. Water is admitted at a controlled rate of 0.026 kgs-¹ at one end and air at a rate of 5 x 104 kgs¹ in the same direction. The density of water is 1000 kgm³, and the density of air is 1.2 kgm³. Determine the mass flow rate, the mean density, gas void fraction, and the superficial velocities of the air and water. Answer: 0.02605 kgs-1, 61.1 kgm-3, 0.94, 0.822 ms-1, 0.051 ms-1