Investigation of collector flow for 1:30 scale solar chimney power plant model

Investigations of the flow field in scaled solar chimney power plant model were carried out using a two pronged approach: Experiments were carried out for a 1:30 scale model of the Manzanares solar chimney power and accompanying numerical simulations. Emphasis was on investigating the hydrodynamic stability of developing inward radial Rayleigh-Bénard-Poiseuille flow under the collector of the 1:30 scale model. Temperature measurements under the collector of the model provided the reference data for comparison with results from a direct numerical simulation. The simulation results reveal that both steady longitudinal (streamwise) modes and unsteady oblique disturbance waves are amplified. Steady longitudinal modes with an azimuthal wavelength of approximately 1.5 times half-height of the collector exhibit the strongest spatial growth. Towards the collector outflow (or inflow to the chimney), the steady modes appear to merge and the growth rates are attenuated as a result of the strong streamwise flow acceleration. A scaling analysis suggests that the present results are relevant for the design and operation of realistic large-scale solar chimney power plants. Based on the present investigation, buoyancy-driven instability and coherent longitudinal flow structures are to be expected for full-size solar chimney power plants. The coherent flow structures will affect the heat transfer and total pressure losses in the collector.