In the distal approach, beam steering is accomplished using a micromechanical scanner-either a microelectromechanical systems (MEMS)-type device or a piezoelectric transducer (PZT) tube integrated in ...the distal tip of the endoscope.2, 3 While this approach has shown some very promising results in terms of achievable resolution and FOV, its scalability remains to be proven since, to the best of our knowledge, the smallest diameter currently achieved is 1 mm.4 In the proximal approach, scanning and focusing of the light is achieved using appropriate spatial modulation of the light before it is coupled into the optical fiber (see Fig. 1). Because this method of proximal spatial light modulation (PSLM) does not require any additional microoptics or micromechanics at the distal end, it enables, in the opinion of the authors, the greatest potential for miniaturization.
The paper deals with numerical simulation of the retort boiler fired with solid fuel. Such constructions are very popular for heating systems and their development is mostly based on the designer ...experience. The simulations have been done in ANSYS/Fluent package and involved two numerical models. The former deals with a fixed-bed combustion of the solid fuel and free-board gas combustion. Solid fuel combustion is based on the coal kinetic parameters. This model encompasses chemical reactions, radiative heat transfer and turbulence. Coal properties have been defined with user defined functions. The latter model describes flow of water inside a water jacked that surrounds the combustion chamber and flue gas ducts. The novelty of the proposed approach is separating of the combustion simulation from the water flow. Such approach allows for reducing the number of degrees of freedom and thus lowering the necessary numerical effort. Decoupling combustion from water flow requires defining interface boundary condition. As this boundary condition is unknown it is adjusted iteratively. The results of the numerical simulation have been successfully validated against measurement data.
•New decoupled modelling of small scale boiler is proposed.•Fixed-bed combustion model based on kinetic parameters is introduced.•Decoupling reduced the complexity of the model and computational time.•Simple and computationally inexpensive coupling algorithm is proposed.•Model is successfully validated against measurements.
