scholarly journals Lagrange Discrete Ordinates: A New Angular Discretization for the Three-Dimensional Linear Boltzmann Equation

2015 ◽  
Vol 180 (3) ◽  
pp. 273-285 ◽  
Author(s):  
Cory D. Ahrens
Keyword(s):  
Boltzmann Equation ◽  
Three Dimensional ◽  
Linear Boltzmann Equation ◽  
Discrete Ordinates ◽  
Angular Discretization

scholarly journals Accelerated Solution of Discrete Ordinates Approximation to the Boltzmann Transport Equation for a Gray Absorbing–Emitting Medium Via Model Reduction

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
John Tencer ◽  
Kevin Carlberg ◽  
Marvin Larsen ◽  
Roy Hogan
Keyword(s):  
Model Reduction ◽  
Three Dimensional ◽  
Accurate Solution ◽  
High Order ◽  
Discrete Ordinates ◽  
Test Problems ◽  
Boltzmann Transport ◽  
Reduced Basis ◽  
Radiative Intensity ◽  
Angular Discretization

This work applies a projection-based model-reduction approach to make high-order quadrature (HOQ) computationally feasible for the discrete ordinates approximation of the radiative transfer equation (RTE) for purely absorbing applications. In contrast to traditional discrete ordinates variants, the proposed method provides easily evaluated error estimates associated with the angular discretization as well as an efficient approach for reducing this error to an arbitrary level. In particular, the proposed approach constructs a reduced basis from (high-fidelity) solutions of the radiative intensity computed at a relatively small number of ordinate directions. Then, the method computes inexpensive approximations of the radiative intensity at the (remaining) quadrature points of a high-order quadrature using a reduced-order model (ROM) constructed from this reduced basis. This strategy results in a much more accurate solution than might have been achieved using only the ordinate directions used to construct the reduced basis. One- and three-dimensional test problems highlight the efficiency of the proposed method.

scholarly journals Radial Turbine Design for Solar Chimney Power Plants

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 674
Author(s):  
Paul Caicedo ◽  
David Wood ◽  
Craig Johansen
Keyword(s):  
Power Plants ◽  
Reference Frames ◽  
Three Dimensional ◽  
Discrete Ordinates ◽  
Large Area ◽  
Solar Chimney ◽  
Cfd Simulations ◽  
Radial Turbine ◽  
Design Changes ◽  
Turbine Design

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.

Denovo: A New Three-Dimensional Parallel Discrete Ordinates Code in SCALE

2010 ◽  
Vol 171 (2) ◽  
pp. 171-200 ◽  
Author(s):  
Thomas M. Evans ◽  
Alissa S. Stafford ◽  
Rachel N. Slaybaugh ◽  
Kevin T. Clarno
Keyword(s):  
Three Dimensional ◽  
Discrete Ordinates
Sign in / Sign up

Export Citation Format

Share Document