The study of airflow and contaminant transport in airliner cabins is very important for creating a comfortable and healthy environment. This paper shows the results of such a study by conducting experimental measurements and numerical simulations of airflow and contaminant transport in a section of half occupied, twin-aisle cabin mockup. The air velocity and air temperature were measured by ultrasonic and omni-directional anemometers. A gaseous contaminant was simulated by a tracer gas, sulfur hexafluoride or SF 6 , and measured by a photoacoustic multi-gas analyzer. A particulate contaminant was simulated by 0.7 μm Di-Ethyl-HexylSebacat (DEHS) particles and measured by an optical particle sizer. The numerical simulations used the Reynolds averaged Navier-Stokes equations based on the RNG k-ε model to solve the air velocity, air temperature, and gas contaminant concentration; and employed a Lagrangian method to model the particle transport. The numerical results quantitatively agreed with the experimental data while some remarkable differences exist in airflow distributions. Both the experimental measurements and computer simulations were not free from errors. A complete and accurate validation for a complicated cabin environment is challenging and difficult.

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Summary This paper presents an innovative conceptual design for small modular reactors, the reduced‐moderation small modular reactor (RMSMR), for the sustainable use of nuclear resources. The concept is established by a modification of the well‐understood pressurized water reactor technology. A reduced‐moderation lattice and heavy‐water coolant are used to yield an epithermal‐to‐fast neutron spectrum, which is beneficial for attaining a large conversion ratio and reducing the burnup reactivity swing throughout the core lifetime. Two‐dimensional pin cell and three‐dimensional core burnup calculations are performed to systematically analyze the neutronics influences of important parameters, such as the coolant type, moderator‐to‐fuel ratio, and fuel type. The RMSMR adopts a three‐zone uranium‐thorium dioxide fuel configuration to flatten the power distribution and ensure a negative void coefficient. The radial and axial blanket regions are found to enhance the breeding effect. The proposed RMSMR can sustain power generation of 100 MWe for 7 years without refueling and achieve a conversion ratio of 0.85 at the end of the cycle. Numerical simulations indicate that the proposed concept has satisfactory shutdown margins and reactivity coefficients and conservative thermal‐hydraulic safety. The RMSMR may be a promising candidate to fill the gap between light‐water reactors and fast breeder reactors.

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