Microstructured reactor as a pre-turbo catalytic converter

The idea of a structured catalytic converter placed immediately after engine exhaust valves, thus operating on high gas temperature and velocity, is explored. The assumption is that major part of the reactor operates in the entry region where Nusselt and Sherwood numbers are highly enhanced. In this work, flow resistances as well as heat and mass transfer coefficients were studied for gas velocities exceeding 50 m/s. Consequently, the transition range (between laminar and turbulent flows) was reached. The comparison with classic monolith has shown significant improvement in heat or mass transfer paid by slight increase in flow resistance

Analogia transportu ciepła i masy : dyskusja problemu

The study deals with the heat and mass transfer analogy developed for both laminar and turbulent flows. The Chilton-Colburn and Léveque analogies are discussed. The Fourier-Kirchhoff equations covering the heat and mass transport as well as their theoretical solutions are also described. The ratio of Schmidt-to-Prandtl number for gases and liquids, obtained using the film and the penetration models, are discussed.Praca poświęcona jest tematyce analogii transportu ciepła i masy dla przepływu laminarnego i turbulentnego. Omowiono analogie Chiltona-Colburna oraz Leveque'a. Opisano także rownania Fouriera-Kirchhoffa dla transportu ciepła i masy oraz ich teoretyczne rozwiązania. Przedstawiono stosunek liczby Schmidta do Prandtla dla gazow i cieczy uzyskany przy zastosowaniu modeli filmu i penetracji

Flow resistance, heat and mass transfer for triangular short-channel structures. Experiments

Trójkątne struktury krótkokanałowe są bardzo krótkimi monolitami o kształcie przekroju poprzecznego kanału zbliżonym do trójkąta równobocznego. Długość kanału struktury jest na tyle krótka, że w przeważającej jego części, występuje rozwijający się przepływ laminarny. Zjawisko to powoduje znaczny wzrost współczynników wnikania ciepła i masy, ale też wzrost oporów przepływu w porównaniu z klasycznymi monolitami o długich kanałach. Podczas pomiarów wnikania ciepła struktury krótkokanałowe były ogrzewane płynącym przez nie prądem elektrycznym. W celu uzyskania rozwiązania dla transportu masy zastosowano analogię transportu ciepła i masy dla przepływu laminarnego. Opory przepływu mierzono przy pomocy mikromanometru Recknagla i miernika elektronicznego. Wyniki otrzymane dla struktur trójkątnych porównano z najczęściej używanymi monolitami ceramicznymi i złożem ziaren usypanych.Triangular short-channel structures are very short monoliths of triangular cross-sectional channel shape. The length of the channel structure is so short, that for the most part of the channel, the developing laminar flow occurs. This phenomenon leads to highly enhanced heat and mass transfer, but the flow resistance is increased as well compared with classic long channel monoliths. During the heat transfer experiments the structures were heated by strong electric current flowing directly through them. The heat transfer experimental results were transformed to the mass transfer representation using heat and mass transfer analogy for the laminar flow. The flow resistance was measured using the Recknagel micromanometer and electronic indicator. The results obtained for the triangular structures were compared with the commonly used ceramic monolith and packed bed

Mass transport and kinetics in structured steel foam reactor with Cu-ZSM-5 catalyst for SCR of NOxNO_x with ammonia

Continued research on improving heat and mass transfer properties of structured catalysts is essential for the development of an effective catalytic system. In this paper, the transfer parameters (mass and heat) and pressure drop across reactors prepared with metal foams of different materials (FeCrAl and Al) and PPI (pores per inch) are presented. The mass transfer parameter was determined by correlation using the Chilton–Colburn analogy, and the heat transfer and pressure drop parameters were determined experimentally. Additionally the kinetic properties of a short channel reactor structure based on metallic foams and template-less synthesized ZSM-5 were determined for the selective catalytic reduction (SCR) of NO with ammonia and compared to commonly used commercial solutions – i.e. packed bed and honeycomb monolith reactor structures