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The present study investigated the potential protective effects of cerium oxide nanoparticles (CNP) on human retinal pigment epithelium (ARPE-19) cells damaged by hydroxychloroquine (HCQ). Toxicity of HCQ on the ARPE-19 cells was explored with a dose response trial. CNP rescue both a pre-treatment protocol, where CNP were applied 24 hours prior to HCQ application and a simultaneous treatment protocol where both CNP and HCQ were applied together, were used. In the dose response trial, 250 µM HCQ showed 51.84% cell viability after 24 hours and 32.75% after 48 hours time period. This was selected as model HCQ dose for rescue trials. The simultaneous treatment trials did not show a significant increase in viability compared to model toxic dose. The CNP pre-treatment trials showed a significant increase in cellular viability compared to model toxic dose with 68.03% ± 3.27 viability (p = 4.56E−05) at 24 hours and 51.85% ± 4.96 (p = 1.18E−05) at 48 hours time period. CNP pre-treatment showed significant protection of cells from HCQ induced toxicity. The difference in efficacy of simultaneous and pre-treatment is hypothesized to lie in the cellular localization of CNP. Furthermore, including the reactive oxygen species (ROS) scavenging properties of CNP seems to be responsible for protection, the effect of CNP on autophagosome and lysosome colocalization are also hypothesized to play a significant role.

This paper describes two patients with squamous cell carcinoma (SCC) of the periocular and periorbital skin who presented with trigeminal neuralgia. Both patients had previous cutaneous SCC of the scalp treated successfully with surgical resection but later presented with neuro-ophthalmic findings suggesting perineural invasion (PNI) of SCC. PNI of SCC in the periocular skin or orbit can lead to devastating effects if malignant cells seed into the orbit and adjacent cranial nerves as our two patients developed an orbital apex syndrome. Patients with a history of SCC of the scalp and forehead who later develop neuro-ophthalmological deficits or patients with persistent ocular symptoms should, in particular, be followed with a low threshold for cutaneous SCC or PNI of recurrent disease. SCC metastasizing into the periocular tissues and orbit by neural invasion is rare and carries a poor prognosis. The urgency for a prompt diagnosis and evaluation by a multidisciplinary team is warranted to prevent untoward outcomes of this skin cancer.

This paper presents the results of a study of fluid flow and heat transfer of liquid hydrogen in a cryogenic storage tank with a heat pipe and an array of pump-nozzle units. A forced flow is directed onto the evaporator section of the heat pipe to prevent the liquid from boiling off when heat leaks through the tank wall insulation from the surroundings. An axisymmetric computational model was developed for the simulation of convective heat transfer in the system. Steady-state velocity and temperature fields were solved from this model by using the finite element method. Forty five configurations of geometry and velocity were considered. As the nozzle fluid speed increases, the values of the maximum, average, and spatial standard deviation of the temperature field decrease nonlinearly. Parametric analysis indicates that overall thermal performance of the system can be significantly improved by reducing the gap between the nozzle and the heat pipe, while maintaining the same fluid speed exiting the nozzle. It is also indicated that increased inlet tube length of the pump-nozzle unit results in slightly better thermal performance. Increased heat pipe length also improves thermal performance but only for low fluid speed.

This study compares thermal environment of two air distribution systems in an office setting. Airflow, heat and mass (water vapor and contaminant gas) transfer in steady-state condition are modeled for an underfloor air distribution system and an overhead air distribution system. The models include a typical cubicle in a large office floor with a chair, a desk with a personal computer on top, and heat sources such as seated person, desktop computer, and lights. For underfloor air distribution system, cool air enters the occupied zone through an inlet located at the floor level supplying a vertical upward inflow. Three different locations of the inlet diffuser are considered. For overhead air distribution, the inlet is located on the ceiling with slower and cooler inflow. Three inlet angles are considered. For both systems, the air return location is on the ceiling at the same place. Distributions of velocity, temperature, relative humidity, and contaminant concentration in various cases for both systems are computed. Thermal comfort factors are assessed for the two systems. The results are compared among cases of each system, as well as between two typical cases of the two systems and to experimental data for an actual office building given in literature. The results provide a detailed understanding of air transport and its consequence on thermal comfort and indoor air quality that are useful for office building air conditioner design. It is found that underfloor system gives better performance than overhead system in contaminant removal and significantly in energy saving while maintaining the same thermal comfort condition.

This paper presents a distributed model of heat transfer in a self-heating unit for group meals and its numerical simulation. A magnesium alloy and water exothermic reaction provides the necessary energy. The resulting governing equations of chemical reaction and heat conduction that depicts the heater performance were solved to develop an approximate analytical solution, to which experimental data found from literature were compared and curve fitted. Then, a model of a complete food-heating unit for group meals, which include a stack of four sets of food tray, heating tray, and heater sandwiched between them, as well as the cardboard container, was developed. The governing equations for heat conduction in the complete model were solved. The response in thermal performance of the heating system to the parameters that influence heating profiles of the heater such as decay constant and heat generation capacity were studied. The results show that the system thermal performance is most significantly affected by heat generation and a proper combination of heaters with different heat generation capacity can improve temperature uniformity between food trays. The results are useful for designing and optimizing self-heating multi-food tray units.

This paper presents air velocity and temperature distribution in a refrigerated warehouse. The refrigerated space under study has a set of ceiling-type cooling units installed in front of the arrays of stacks of palletized product packages. Numerical solutions of the steady-state airflow and heat transfer were done using a complete three-dimensional model and an equivalent two-dimensional model. The results obtained from both models were found to be in good agreement with each other. A parametric analysis was performed using the equivalent model with various values of blowing air velocity and locations of the cooling units. It was found that a better cooling effectiveness and uniformity of temperature in the refrigerated space could be achieved by using higher blowing air velocity and/or locating the cooling units lower and closer toward the arrays of product packages.

This paper presents the transient analysis of fluid flow and heat transfer in a zero-boil-off cryogenic storage tank of liquid hydrogen. The system includes a tank with a cylindrical wall and oblate spheroidal top and bottom, a heat pipe located along the symmetric axis of the tank, and an active circulator consisting of a pump-motor assembly and a spray nozzle. Whenever the maximum temperature inside the tank reaches the boiling point under the working pressure in the tank, the pump is activated to create a forced flow at the nozzle to cool down the heated fluid. After a preset interval of 1 h, the pump is shut down and goes on standby until the maximum temperature reaches its threshold again, and then the pump starts a new cycle. The transient simulation allows the visualization of flow-field and temperature distributions, as well as the computation of maximum and mean temperatures of the fluid in various stages of the pump cycle. This information reveals insights into the characteristics of the stored liquid hydrogen and can assist in optimizing the location of temperature sensors, which provide input to the control system.

This paper presents a three-dimensional analysis for thermal comfort and contaminant removal in a hospital operating room. The room model includes a patient lying on an operating table, four surgical staff members standing around, and surgical lights above the patient. Cold clean air is supplied to the room through high sidewall grilles and exhausted through low sidewall grilles on the opposite wall. Steady-state heat and mass transfer in the room are simulated by employing computational fluid dynamics modeling approach. Solutions of the distribution of airflow velocity, temperature, relative humidity, and contaminant concentration are presented and discussed. The simulation results show a good agreement with experimental data from the literature. The predicted mean vote (PMV) is calculated for assessing thermal comfort of the occupants. The contaminant removal effectiveness (CRE) and the mean contaminant concentration in the breathing zone are used to assess the ventilation performance of the room. Effects of horizontal locations of supply and exhaust grilles on thermal comfort and contaminant removal are explored. Regression models for thermal comfort and contaminant removal as functions of these locations are built for design optimization. It is found that an overall better performance can be achieved by placing the supply grilles closer to the vertical centerline of the wall while the location of the exhaust grilles is somewhat insignificant.

A parametric analysis on the effect of using a ceiling fan in an air-conditioned room is performed by two-dimensional (2D) numerical simulation of steady state airflow and heat transfer. Thermal comfort analysis is done for a person standing in a room with an inlet and an outlet for air conditioning and a ceiling fan. Representative three-dimensional (3D) simulation is also performed for the comparison of results obtained by using 2D and 3D models. Distributions of velocity, temperature, and relative humidity are presented. Different cases in which the ceilings fan may be not in use or in use with different air speed normal to the plane of fan blades due to different rotational speeds are considered. Predicted mean vote is computed and used to assess the thermal comfort characteristics. It is found that as the normal air speed from the fan increases, thermal comfort significantly shifts toward the cooler scale to allow higher supply air temperature or higher heat load in the room while maintaining the same comfort level.

This paper presents a steady-state analysis of fluid flow and heat transfer in a zero boil-off cryogenic liquid hydrogen storage tank in microgravity environment. The storage tank is equipped with an assembly of an inlet tube and a nozzle head that contains many nozzles on its front face. Liquid hydrogen is cooled by an external cryocooler, flows along the nozzle head assembly, penetrates into the bulk liquid through the nozzles in order to prevent the boiling off due to heat leak from the surroundings through the tank wall insulation, exits the tank through an annular outlet opening coaxial with the inlet, and then goes back to the external cooling system. Eleven cases for different geometry settings were analyzed. Typical distributions of velocity and temperature are presented. The results show that thermal performance of the system can be improved by increasing the inlet diameter and properly selecting the depth and the span of the nozzle head.

This paper presents a study on fluid flow and heat transfer of liquid hydrogen in a zero boil-off cryogenic storage tank in a microgravity environment. The storage tank is equipped with an active cooling system consisting of a heat pipe and a pump–nozzle unit. The pump collects cryogen at its inlet and discharges it through its nozzle onto the evaporator section of the heat pipe in order to prevent the cryogen from boiling off due to the heat leaking through the tank wall from the surroundings. A three-dimensional (3-D) finite element model is employed in a set of numerical simulations to solve for velocity and temperature fields of liquid hydrogen in steady state. Complex structures of 3-D velocity and temperature distributions determined from the model are presented. Simulations with an axisymmetric model were also performed for comparison. Parametric study results from both models predict that as the speed of the cryogenic fluid discharged from the nozzle increases, the mean or bulk cryogenic fluid speed increases linearly and the maximum temperature within the cryogenic fluid decreases.

This work presents how approximate solution methods were introduced in a graduate level course of Theory of Elasticity. The three methods introduced are the finite difference method, the finite element method, and the boundary element method. All methods are exemplified by the problem of a thick-walled cylinder subject to internal pressure with an axisymmetric response. Choosing a single problem to introduce the three methods demonstrates accuracy and efficacy of each method. © 2006 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 120–134, 2006; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20070

Data from conical-shaped film cooling holes are extremely sparse in open literature, especially the cooling uniformity characteristic, an important criterion for evaluating any film cooling design. The authors will compare the performance of conical-shaped holes to cylindrical-shaped holes. Cylindrical-shaped holes are often considered a baseline in terms of film cooling effectiveness and cooling uniformity coefficient. The authors will study two coupons with conical-shaped holes, which have 3° and 6° diffusion angles, named CON3 and CON6, respectively. A conjugate heat transfer computational fluid dynamics model and an experimental wind tunnel will be used to study these coupons. The three configurations: cylindrical baseline, CON3, and CON6, have a single row of holes with an inlet metering diameter of 3 mm, length-to-nominal diameter of 4.3, and an injection angle of 30°. In this study, the authors will also take into account the heat transfer into the coolant flow from the coolant channel. In other words, the coolant temperature at the exit of the coolant hole will be different than that measured at the inlet, and the conjugate heat transfer model will be used to correct for this difference. For the numerical model, the realizable k-ɛ turbulent model will be applied with a second order of discretization and an enhanced wall treatment to provide the highest accuracy available. Grid independent studies for both cylindrical-shaped film cooling holes and conical-shaped holes will be performed, and the results will be compared to data in open literature as well as in-house experimental data. Results show that conical-shaped holes considerably outperform cylindrical-shaped holes in film cooling effectiveness at all blowing ratios. In terms of cooling uniformity, conical-shaped holes perform better than cylindrical-shaped holes for low- and midrange blowing ratios, but not at higher levels.

Film cooling performance is affected by many factors, for example: geometrical factors (injection angle, length-to-hole diameter ratio, surface roughness, etc.) as well as flow conditions (mass flux ratio, momentum flux ratio, turbulence intensity, etc.). In most of the film cooling literature, film effectiveness has been used as criterion to judge and/or compare between film cooling designs. Uniformity is also a critical factor, since it is determining how well the coolant spreading out downstream to protect the working surface in a gas turbine engine. Better cooling uniformity will reduce thermal stress associated with gas turbine components. A flat plate with round holes embedded in a trench is considered in this study. Although the trench may have an adverse effect on fan-shaped film hole cooling, it tremendously increases the performance of the round-hole film cooling technique in terms of film cooling effectiveness. An experimental study at CATER facility has shown that the cooling effectiveness can be retained by the addition of a trench feature while using only half a number of cooling holes. The current work is conducted based on the numerical study with a validation from in-house experimental works at CATER and the experiments from the literature. The experimental temperature distribution is captured by using Temperature Sensitive Paint and then span-wised effectiveness is calculated. The studied input parameters include flow variables (blowing ratio, BR and momentum ratio, MR) and geometrical parameters (trench-depth-to-diameter ratio, s/D and pitch-to-diameter ratio, p/D). A comparison of contributions of studied factors is investigated by using Response Surface Methodology technique. The spatially adiabatic film cooling effectiveness is selected as the primary output in the design of experimental analysis. Since the nonlinear behavior of all input factors are also of interest, three levels of each parameter will be considered. The well-know Box and Behnken design is employed to carry on this sensitivity analysis. With this method, the current study only requires 25 runs to obtain a quantified comparison of the contribution of each involved effects.

Large Eddy Simulations were performed on a simple angle cylindrical film cooling hole with a 35° inclination angle and a length-to-diameter ratio of 3.5. A density ratio of 1.25 and velocity ratio of 0.80 was employed, yielding a mass flux ratio of 1.0 and momentum flux ratio of 0.80. Three different discretization schemes were used in otherwise identical simulations: bounded central differencing, pure second-order upwind, and pure secondorder central differencing. The results of these three cases are compared with experimental data from open literature studies in terms of surface adiabatic effectiveness, mean temperature and velocity fields, and unsteady turbulence characteristics. The pure central differencing scheme was found to perform the best in this film cooling scenario, while the upwind scheme also preformed well. The bounded central scheme compared poorly with the experimental data and the other two schemes. The present investigation was made in an attempt to further explore the abilities of Large Eddy Simulations to resolve the complex flow structure arising from the injection of a film cooling jet into a turbine hot gas path.

This paper presents a numerical modeling and simulation of heat transfer in a food self-heating unit for group meals. A model of a water-activated heater based on an exothermic reaction was developed. The resulting governing equations of heat conduction and chemical reaction were solved for an analytical approximate solution, to which experimental data found from literature were compared and curve fitted. Then a model of a complete food-heating unit, which includes a stack of four sets of food tray, heating tray, and heater sandwiched between them, as well as the cardboard container, was developed. A system of governing equations for heat transfer in the composite medium for the complete model was solved. Numerical solution of temperature distribution within the food-heating unit is presented. The responses in thermal performance of the heating system to the parameters that influence heating profiles of the heater such as decay constant and heat generation were studied in order to improve the thermal performance of the heating system. The results are useful for designing and optimizing self-heating systems for food served to groups of many people.Copyright © 2010 by ASME

When collecting the energy of the sun for domestic use, there are several options, which include photovoltaic cells and evacuated tube collectors. Arrays of evacuated tube collectors are used to heat water for domestic applications, supplementing the use of a typical hot water heater, while photovoltaic cells transform the sun’s radiation into electricity. The benefit of the tube collectors is that they supplement an appliance that uses a fairly large amount of electricity when compared to others in an average home. However, the collectors cannot operate during the night time and produce more hot water than needed at their peak operation point. A thermal storage unit can be used to even out the conversion of energy throughout the day to solve this problem. This study proposes a system using paraffin wax to store thermal energy collected during the day by melting the wax. The system makes use of a finned heat exchanger, with paraffin wax on the shell side, and glycol on the tube side as the heat transfer fluid. It also includes a separate loop for water to flow through and receive thermal energy from the melted wax. Although the wax used in the study is quite effective at storing thermal energy, it has the problem of low conductivity. So, fins are added to the storage and extraction loops to increase the wax’s thermal conductivity. The fins not only help to melt the wax more quickly but also act as nucleation sites when the wax freezes. Once all the wax is melted, energy can be exchanged from it to heat water. When creating such a unit, it is useful to have simulation tools to guide its design. One such tool is FLUENT, which will be used in this study to create a simulation of part of the unit. The simulation will be compared to experimental data from a prototype unit and evaluated based upon its strengths and weaknesses.Copyright © 2010 by ASME

The analysis of a single chamber micropump with a diaphragm driven by a pulse train of external pressure and two passive check valves at inlet and outlet is performed. The model for the micropump is developed based on the fundamentals of fluid mechanics and theory of plates with quasi-static approximation. The simulation results are compared with existing experimental data. They are in good agreement on flow rate and in reasonable agreement on backpressure for low driving frequency up to 3 Hz. It is found that the flow rate increases as the driving frequency increases or the backpressure decreases. The results also predict that a duty cycle of 50% results in the highest flow rate at the same frequency and actuating pressure. Also, a higher actuating pressure yields a higher flow rate. The model presented here can effectively assist the design process of micropumps since the model is directly related to the basic design parameters such as geometric dimensions and material properties.Copyright © 2010 by ASME

End-wall film cooling technique is an advanced technology which has been employed in modern gas turbines to protect the surface of the end-wall. The sophistication of this technique has allowed an increase in the combustor outlet temperature, resulting in higher engine overall efficiency. Several criteria are used to judge the performance of film cooling; one of them is film cooling effectiveness (ETA) which has been adopted in most of the literature nowadays. In part I of the investigation, we aim to withdraw an overall correlation between film cooling effectiveness and flow conditions and geometric parameters. A lot independent parameters, that could play a role in film cooling performance, are: blowing ratio, cooling mass flow rate, pitch distance, geometry of the hole, injection angle, and inlet to exit hole-area ratio to name a few. But we need to screen some factors out that seem to be more potentially affect the output based on previous experiences (or available literature), or by conducting pilot runs. Due to nature of preliminary investigation in this part I, the authors found that blowing ratio (BR), density ratio (DR), jet inclination angle (α) and hole length-to-diameter ratio (L/D) are more important and are selected as investigated factors. A full design of experiment is then performed and it is worth to note here that typical values are assigned for those less important factors and they are kept constant in the sensitivity analysis. Regression equation is also extracted to predict the spatial average film cooling effectiveness (ETAaa ). This investigation is supported by numerical analysis where the solution of the computational domain is performed using FLUENT package [1]. Second order schemes are used to provide the highest accuracy available. The realizable k-e model (RKE) is integrated in this work with enhanced wall treatment for all its runs. For the baseline case, computational fluid dynamic (CFD) result is compared against actual experimental data where the experimental baseline work was conducted for a row of cylindrical holes on a flat plate at the Center of Advanced Turbine and Energy Research (CATER). Temperature distribution is captured by using the temperature sensitive paint (TSP) technique and the output design parameter is then calculated.Copyright © 2009 by ASME

This paper presents the three-dimensional (3D) modeling and simulation of heat transfer within a portable blood cooling system with respect to space and time. The cooling system under study includes a cooler box with two cooling cylinders and eight blood bags. The cooler has the shape of a rectangular box with walls made of thermal-insulation material. The cooling cylinders protrude into the inner space through the bottom of the cooler box. Eight blood bags are arranged around these two cooling cylinders. The cooling cylinders use desiccant absorbing agents in combination with evaporative processes under vacuum pressure to achieve the cooling effect. Transient thermal response of the system is simulated by employing a computational approach. The computational domain includes the air inside the cooler box and the blood inside the blood bags. Heat from the surroundings penetrating the system through the insulation walls of the cooler box is included in the model. It is assumed that initially the blood is at the uniform ambient temperature. Once the cooling cylinders are activated, they draw heat from the air and the blood inside the cooler box. A lumped-parameter model is used to model the heat drawn by the cooling cylinder. The resulting solution of temperature distribution within the blood bags and the air in the cooler box is presented in the form of graphical visualization. Representative temperatures within the blood bags are presented as functions of time during a period of 12 hours. The computational model and results will be useful for the development and optimization of the design of portable cooling devices for the transportation of blood and similar biological tissues such as an organ for transplant.Copyright © 2009 by ASME

This paper presents a practical solution to improve the current overall corn ethanol economics. It is our intent in this paper also to focus our attention on extraction of corn ethanol and distillers dry grains with solubles (DDGS) employing the dry milling process since it appears to offer the greatest opportunity for substantial improvement. Alternate corn ethanol wet mill processing for the extraction of gluten protein meal for livestock food is also briefly described. A hybrid integrated steam jet refrigeration/freeze concentration system (ISJR/FCS) is proposed for the extraction of corn ethanol and DDGS in dry milling process. Technical feasibility of substantially reducing corn ethanol first cost on a life cycle basis as well as current operational costs and greenhouse gas emissions is demonstrated employing an actual case study.Copyright © 2008 by ASME

This paper presents the transient analysis of fluid flow and heat transfer in a zero boil-off (ZBO) cryogenic storage tank of liquid hydrogen. The system includes a tank with cylindrical wall and oblate spheroidal top and bottom, a heat pipe located along the symmetric axis of the tank, and an active circulator. The heat pipe has a rounded evaporator section at its end. The active circulator is an assembly of a pump body, a suction tube for collecting fluid inside the tank, and a spray nozzle from which the fluid is discharged onto the evaporator section of the heat pipe, which is kept at a constant low temperature, where the heat is removed passively to the condenser section of the heat pipe located outside the tank and eventually to the ambient via a cryocooler. Whenever the maximum temperature inside the tank reaches the boiling point under the working pressure in the tank, the pump is activated to create a forced flow from the nozzle to cool off the heated fluid. After a preset period of time, the pump is shut down and standby until the maximum temperature reaches its threshold again and then the pump starts a new cycle. The transient simulations allow the visualization of flow field and temperature distribution, as well as the computation of maximum and mean temperatures of the fluid at various stages of the pump cycle.Copyright © 2007 by ASME

This paper presents a study of thermal behavior in a refrigerated warehouse equipped with ceiling type refrigeration unit. A two-dimensional steady-state problem was solved by using computational fluid dynamics modeling and simulation. The computational model includes a refrigerated space at the center plane of an array of 4 piles by 3 stacks of palletized product packages with a evaporator fan refrigeration unit, in which the fan pull air through cooling coil and blow out into the space. A parametric analysis was done based on fourteen simulation cases of conditions including different locations of the refrigeration unit as well as different normal forced air velocities produced by the fan. Typical distributions of velocity and temperature are presented. From the results, it is found that better cooling effectiveness and uniformity of the refrigerated space can be achieved by using higher normal supply air speed or locating the refrigeration unit lower and closer to the array of stacks of product packages.Copyright © 2006 by ASME

This paper presents a steady-state analysis of fluid flow and heat transfer in a zero boil-off cryogenic storage tank for liquid hydrogen. The system includes a tank with cylindrical wall and oblate spheroidal top and bottom, and a cold-spray nozzle head whose face is set perpendicular to the axis of the tank. The nozzle head has many nozzles on its front face. The cold fluid cooled by an external cooling system enters the inlet opening at the top of the tank, follows an axial supply tube to the nozzle head and exits through the nozzles into the bulk fluid inside the tank heated by heat leak from the surroundings. The displaced fluid exits the tank through an annular outlet opening (also at the top of the tank and concentric with the inlet opening) then goes back to the external cooling system. This study considers the transport phenomena in the storage tank only with prescribed fluid flow velocity and temperature at the inlet to represent the external cooling system.Copyright © 2006 by ASME

*† This paper presents a study of fluid flow and heat transfer in a cryogenic storage tank for liquid hydrogen using a three-dimensional model for numerical simulation. The model includes a tank with cylindrical wall and oblate spheroidal top and bottom, a heat pipe located along the axis of the tank, and a pump-nozzle unit that collects fluid at the suction inlet and discharges at its nozzle face onto the cool tip (evaporator) of the heat pipe in order to prevent the fluid to boil off. A steady state condition was assumed. Simulations with different normal speeds of fluid discharged at the nozzle face were run for a parametric analysis. Typical distributions of velocity and temperature are presented. Average speed and maximum temperature for each case are evaluated for assessing mixing and boiling effects, respectively. Simulations using an axi-symmetric model, which represents the case of an array of many pump-nozzle units installed around the heat pipe, were also carried out with the same fluid discharge speeds as those of the three-dimensional cases for comparison. For both models, the results show that as the normal fluid speed at the nozzle increases, the average fluid speed increases whereas the maximum temperature decreases. It is also found that with the same fluid speed discharged normally from the nozzle face the axi-symmetric model gives higher average speed and higher maximum temperature compared to the threedimensional model.

The study of human thermal comfort requires detailed information about distributions of air velocity, air temperature and relative humidity in an occupied zone. Air quality is related to the contaminant distributions and contaminant removal effectiveness in indoor environment. This paper presents an evaluation of thermal comfort and contaminant removal for an office setting with underfloor air distribution system by the use of computational fluid dynamics modeling. A typical single cubicle in a large office floor in steady state condition of airflow as well as heat and mass transfer is investigated for both cooling and heating scenarios. The model includes a typical cubicle in a large office floor with a chair, a desk with a personal computer on its top, and heat sources such as seated people, computer monitor and CPU, and lights. Air enters the occupied zone through an inlet located at the floor level supplying a vertical upward inflow. Five different locations of the inlet diffuser, three different inlet air speeds, and four different loads of heat loss through the floor slab in heating case scenario were considered. Distributions of velocity, temperature, relative humidity, and contaminant concentration in such cases were computed. The results were compared among various simulation cases and showed reasonable agreement with experimental data taken from related literature.

This paper uses airflow simulations to evaluate different ventilation systems on an operating room (OR). This study compares air distribution systems for an operating room by use of computational fluid dynamics (CFD) modeling. The air supply distribution and exhaust arrangements were modeled for a directional air flow system where air moves across the space from the high-pressure supply area to the low pressure exhaust area. Calculations were done to model a typical operating room in a steady-state condition with inclusion of object such as surgical lights, operating table, heat sources such as surgical staff and a patient, side-wall supply grille and exhaust air grilles. The discharge angle for the side-wall supply grille was varied from 0 to 45 degrees. Air return locations were also studied. One and two air exhaust outlet sites inside the surgical suite were considered. In the two-exhaust outlet configuration, one position was close to the floor and the other position was high on the wall. Simulations with combinations of 1:0, 1:0.343, 0.343:1, and 1:1 flow rates between the two return locations were performed. Predictions for the air movement, room temperature, room relative humidity, and concentration of contaminants within the operating room are shown. Analysis of these predictions is discussed. The supply and exhaust conditions of the ventilation air flow are shown to play an important role in the control of air quality. Results show good agreement with experimental data.Copyright © 2004 by ASME