The rotating disk is a useful laboratory tool for measuring dissolution of solids. The relationship for the mass transfer coefficient is Sh= 0.62Re^0.5. Se^1/5 where Re= r^2ωrho/μ

where ω is the rotation speed and r is the disk radius. The length parameter in the Sherwood number is the radius. Consider a rotating disk with a 3.0 cm diameter, rotating at 250.0 rpm, with a solid dissolving into a liquid at 25.0°C with the properties of water. The diffusion coefficient of the dissolved solid in water is 2.00x10-9 m²/s, and the solubility of the solid in the liquid is 0.200 kg/m².

Required:
Determine the initial rate of dissolution in kg/s. The initial dissolution rate occurs when there is zero dissolved solid in solution.

Water at 70°f and streams enter the mixing chamber at the same mass flow rate, determine the temperature and the quality of the exiting stream. 0 psia is heated in a chamber by mixing it with saturated water vapor at 20 psia. if both streams enters the mixing chamber at the same mass flow rate, determine the temperature and the quality of the existing system.

Water at the rate of 1 kg/s is forced through a tube with a 2.5 cm inner diameter. the inlet water temperature is 15°c, and the outlet water temperature is 50°c. the tube wall temperature is 14°c higher than the local water temperature all along the length of the tube. what is the length of the tube?

Tom is having a problem with his washing machine. he notices that the machine vibrates violently at a frequency of 1500 rpm due to an unknown rotating unbalance. the machine is mounted on 4 springs each having a stiffness of 10 kn/m. tom wishes to add an undamped vibration absorber attached by a spring under the machine the machine working frequency ranges between 800 rpm to 2000 rpm and its total mass while loaded is assumed to be 80 kg a) what should be the mass of the absorber added to the machine so that the natural frequency falls outside the working range? b) after a first trial of an absorber using a mass of 35 kg, the amplitude of the oscillation was found to be 10 cm. what is the value of the rotating unbalance? c) using me-3.5 kg.m, find the optimal absorber (by minimizing its mass). what would be the amplitude of the oscillation of the absorber?