Shell-side distribution and the influence of inlet conditions in a model of a disc-and-doughnut heat exchanger

Measurements of wall pressure and of three orthogonal velocity components with their corresponding fluctuations are reported for two systems of alternating and equi-spaced doughnut and disc baffles axisymmetrically located in a water turbulent pipe flow, simulating the isothermal shell-side flow in shell and tube heat exchangers. The influence of inlet Reynolds number and of asymmetric inlet flow conditions was studied for two geometries. The velocity field was dominated by the pressure gradient and the flow around each individual baffle was influenced by the relative position of its neighbouring baffles.List of symbols C _p wall static-pressure coefficient - D internal diameter of upstream and downstream pipes (mm) - D _s internal diameter of test section (mm) - d _d disc diameter (mm) - d _c doughnut-hole diameter (mm) - l baffle-pitch (mm) - l _i entrance length in the model before first baffle (mm) - l ₀ exit length in the model after last baffle (mm) - mass flow rate (kg/s) - p local wall-static pressure (mm H₂O) - p density of water (1.006 kg/dm³ at 17°C) - Re _b Reynolds number based on bulk velocity - U _b bulk velocity - U _max maximum centre-line axial velocity (ms^–1) - x, y, z Cartesian coordinates - mean and turbulent velocity components along x, y, z respectively