Natural Convection and Thermal Stratification in a Biomass Oven Fueled by Non-Carbonized Kesambi Leaf Briquettes: An Experimental Study

Review of experimental study on melt pool natural convection behavior

The advanced very high resolution radiometer multichannel sea surface temperature (MCSST) retrieval technique provides global algorithm accuracy statistics generally showing a bias of less than 0.1°C and an rms error of less than 0.7°C when compared to colocated drifting buoy in situ data in the absence of aerosols. This remaining error is not always random but is shown to be correlated to the air‐sea temperature difference. The MCSST technique is modeled and then compared to in situ data to show this dependency. Atmospheric radiative transfer calculations are used to provide a simulation of satellite retrieval sensitivity to air‐sea temperature differences. Buoy sea surface temperature (SST) and air temperature observations are then presented as experimental verification of the simulation results. Retrieval errors depend both on the mean air‐sea temperature difference conditions present in the data set used to empirically derive the algorithm and on the changes in air‐sea temperature difference conditions relative to the derivation data set mean conditions. Retrieval error is found to respond linearly with air‐sea temperature difference changes. MCSST retrieval errors of 1.0°C can occur for air‐sea temperature difference changes of 7°–10°C from mean conditions when the dual‐window (channels 3 and 4) or triple‐window (channels 3, 4, and 5) algorithms are used. The split‐window (channels 4 and 5) MCSST algorithm is shown to be less sensitive to air‐sea temperature differences. Cross‐product SST (CPSST) and nonlinear SST (NLSST) algorithms are also examined. These algorithms generate results similar to the MCSST algorithm for the dual‐ and triple‐window equations. However, the CPSST and NLSST split‐window algorithms demonstrate greater sensitivity to air‐sea temperature difference changes than do the MCSST split‐window algorithm. Retrieval errors of 1°C can occur for air‐sea temperature difference changes of 10°–12°C from mean conditions. Users of satellite SST retrievals in regions that experience large fluctuations in air‐sea temperature difference should be aware of this possible error source.

In this article a numerical simulation is employed to obtain dimensionless heat transfer in laminar natural convection condition for isothermal bodies which are similar to sphere and cylinder. Then, the numerical results for different bodies are compared with each other to figure out the effect of convexity / concavity on laminar natural convection. A computational fluid dynamics (CFD) codes is used for solving the relevant mathematical expressions for natural convection heat transfer from isothermal bodies. Excellent agreement between the results of the present numerical simulation and available experimental results is observed in the whole laminar flow range 0≤RaA≤108. However, that is why the laminar natural convection from sphere and cylinder with L/D = 1 and a few other shapes turned out to be the same, some of the bodies show better natural convection behavior with specific shapes. In addition, Convexity has small effect on the Nu number for low laminar range of RaA number besides, in convex bodies, removing the sharp edges helps to increase natural convection heat transfer. Finally, it is worth to mention that this numerical simulation reveals that it has the capability to be used as a tool to predict the behavior of flow and heat transfer around isothermal convex / concave bodies.

Experimental study of solid-liquid phase change in the presence of supercooling and natural convection

Thermofluid behaviour of the lead bismuth eutectic target for the spallation neutron source at SIN

Experimental study of the effect of inclination angle on the paraffin melting process in a square cavity

Heat transfer enhancement of phase change materials by fins under simultaneous charging and discharging

Safety systems, like the passive containment air-cooling system, are used to remove heat from a containment during accident conditions in advanced nuclear reactors, including small modular reactors having a steel containment. For the effective performance of the passive containment air cooling system with and without a chimney, it is highly important to understand the natural convection air flow around the containment. The experimental investigation of passive containment air cooling of an experimental test setup with and without a chimney, with a geometry very similar to that of an actual reactor, is presented in this paper. Comparisons between the air-side transient natural convection characteristics with and without a chimney were studied in detail based on the temperature measurement. The effect of a chimney was found to have an adverse effect on natural convection behavior due to possible air recirculation zones and restrictions to air flow due to its present shape.

Close-contact melting and natural convection in unconstrained melting: A parametric study

Experimental investigation on natural convection and thermal stratification of IRWST using PIV measurement

Pressure behavior and heat transfer behavior of air natural convection in an asymmetrically heated vertical channel with a damper

The upper cooling surface temperature of the layer is fixed at the freezing point of 0°C and the lower heating surface temperature is fixed at a prescribed temperature such as 7, 10, 15, 20, 25 and 30°C in this experiment. The bead diameter employed in the porous layer is 5, 11 and 15 mm for glass beads, and 11 mm for steel beads. The layer depth is fixed at 25, 50, 75, 100 and 125 mm. It is found in this investigation that the Nusselt number decreases with decreasing surface temperature heating at the prescribed Rayleigh number due to the maximum density of water, and the effect of the maximum density on natural convection becomes small when the lower heating surface temperature is larger than about 25°C.

As a basis for the development of energy storage systems utilizing crystallization/dissolution of chemical substances, an experimental study is performed for crystallization of ammonium sulfamate from an aqueous solution confined in a rectangular vessel. A molded polycrystal adhering to one of the vertical walls in the vessel was made to grow by cooling the opposite wall. The behavior of natural convection in the solution was visualized using granulated tracers. In addition, local changes in solution temperature were also measured.In the neighborhood of the growing polycrystal, upward flows develope through the decerase in concentration of solution due to crystal growth, as well as by the increase in temperature due to the latent heat of crystallization. Dilute solution transferred upward is retained at the top of the vessel to form a horizontal rolling cell there. After that, ascending dilute solution is retained above the cell, and forms a second cell. Finally, horizontal multi-layers are established in the liquid phase. Moreover, the effects of cooling rate and flow structure on the crystal growth is discussed.

A moving-boundary based dynamic model for predicting the transient free convection and thermal stratification in liquefied gas storage tank

Numerical analysis of natural convection behavior in density stratification induced by external cooling of a containment vessel