COMPARISON OF THEORY AND EXPERIMENT FOR THE FLUID DYNAMIC PERFORMANCE OF CROMOLYN SODIUM INHALERS USED FOR ASTHMA PREVENTION

1980 ◽  
pp. 397-401
Author(s):  
Eugene E. Niemi
Keyword(s):  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Cromolyn Sodium ◽  
Asthma Prevention ◽  
Theory And Experiment

scholarly journals Experimental Investigation and Comparison of the Thermal Performance of Additively and Conventionally Manufactured Heat Exchangers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 574
Author(s):  
Ana Vafadar ◽  
Ferdinando Guzzomi ◽  
Kevin Hayward
Keyword(s):  
Surface Roughness ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Cooling System ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Manufacturing Method ◽  
Industrial Sectors

Air heat exchangers (HXs) are applicable in many industrial sectors because they offer a simple, reliable, and cost-effective cooling system. Additive manufacturing (AM) systems have significant potential in the construction of high-efficiency, lightweight HXs; however, HXs still mainly rely on conventional manufacturing (CM) systems such as milling, and brazing. This is due to the fact that little is known regarding the effects of AM on the performance of AM fabricated HXs. In this research, three air HXs comprising of a single fin fabricated from stainless steel 316 L using AM and CM methods—i.e., the HXs were fabricated by both direct metal printing and milling. To evaluate the fabricated HXs, microstructure images of the HXs were investigated, and the surface roughness of the samples was measured. Furthermore, an experimental test rig was designed and manufactured to conduct the experimental studies, and the thermal performance was investigated using four characteristics: heat transfer coefficient, Nusselt number, thermal fluid dynamic performance, and friction factor. The results showed that the manufacturing method has a considerable effect on the HX thermal performance. Furthermore, the surface roughness and distribution, and quantity of internal voids, which might be created during and after the printing process, affect the performance of HXs.

Virtual Evaluation for Machine Tool Design

2008 ◽  
Author(s):  
Masahiko Mori ◽  
Zachary I. Piner ◽  
Ke Ding ◽  
Adam Hansel
Keyword(s):  
Machine Tool ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Digital Simulation ◽  
Machining Accuracy ◽  
Analysis Model ◽  
Simulation Accuracy ◽  
Theoretical Simulation ◽  
Physical Experiments ◽  
Static Rigidity

This paper presents the virtual machine tool environment Mori Seiki established for the evaluation of static, dynamic, and thermal performance of Mori Seiki machine tools. In this system environment, machining accuracy and quality are the main focus for each individual analysis discipline. The structural analysis uses the Finite Element Method (FEM) to monitor and optimize the static rigidity of the machine tool. Correlation between physical experiments and digital simulation is conducted to validate and optimize the static simulation accuracy. To accurately evaluate and effectively optimize dynamic performance of the machine tool in the virtual environment, the critical modal parameters such as damping and stiffness are calibrated based on experimental procedures which results in precise setup of the frequency response models. Computational Fluid Dynamic (CFD) analysis model is built in the environment so that the thermal perspective of the machine tool is evaluated and thermal deformation is monitored. This paper demonstrates compatibility of the digital simulation with physical experiments and success in integrating theoretical simulation processes with practical Mori Seiki machine tool development.

Empirical Optimization of High Density Plate-Fin Heat Sink for Constant Pumping Power in Low Profile Cooling Application

2005 ◽  
Author(s):  
Kazuaki Yazawa ◽  
Tatsuro Yoshida ◽  
Shinji Nakagawa ◽  
Masaru Ishizuka
Keyword(s):  
Fluid Dynamic ◽  
Dynamic Performance ◽  
High Heat ◽  
Heat Sinks ◽  
High Heat Flux ◽  
Pumping Power ◽  
Low Profile ◽  
Data Points ◽  
Narrow Space ◽  
The Impact

Since the VLSI processors are increasing power in accordance with exponential law, cooling solutions for such as personal computers have been evolving for over a decade. Recent heat sinks are designed with high dense fins and low profile to adapt to a high heat flux source within a slim enclosure. To achieve such compact cooling solution, thin fin and small gap is desirable. In addition, the pumping power is also limited by the allowable narrow space for fans. Thus it is important to minimize the thermal resistance for given pumping power that we define the optimum. Due to the lack of literatures on topic of low profile and high dense fins experiments, an apparatus was specially built to measure the thermal and fluid dynamic performance at the same time. Since such a high dense fin arrangement requires extra space on the sides by manufacturing reasons, the impact of bypass flow needs to be considered. The experiments are carefully carried out and the results are precisely compared with numerical analysis. The numerical model aiming to find the optimum for given pumping power is discussed with extrapolating the data points. This report is concluded with the best configuration of plate fins of low profile heat sinks for a given fan performance.

A Fluid Dynamics Study of a Modified Low-Reynolds-Number Flapping Motion

2010 ◽  
Author(s):  
M. R. Amiralaei ◽  
H. Alighanbari ◽  
S. M. Hashemi
Keyword(s):  
Fluid Dynamics ◽  
Reynolds Number ◽  
Phase Angle ◽  
Fluid Dynamic ◽  
Low Reynolds Number ◽  
Dynamic Performance ◽  
Navier Stokes ◽  
Fluid Forces ◽  
Low Reynolds ◽  
Volume Method

The objective of the present study is to investigate the low Reynolds number (LRN) fluid dynamics of an elliptic airfoil performing a novel figure-eight-like motion. To this mean, the influence of phase angle between the pitching and translational (heaving and lagging) motions and the amplitude of translational motions on the fluid flow is simulated. Navier-Stokes (NS) equations with Finite Volume Method (FVM) are used and the instantaneous force coefficients and the fluid dynamics performance, as well as the corresponding vortical structures are analyzed. Both the phase angle and the amplitudes of horizontal and vertical motions are of great importance to the fluid dynamic characteristics of the model as they are shown to change the peaks of the fluid forces, fluid dynamic performance, and the vortical patterns around the model.

scholarly journals Experimental studies into the fluid dynamic performance of the coolant flow in the mixed core of the Temelin NPP VVER-1000 reactor

2015 ◽  
Vol 1 (3) ◽  
pp. 174-178
Author(s):  
S.M. Dmitriev ◽  
D.V. Doronkov ◽  
Ye.N. Polozkova ◽  
A.N. Pronin ◽  
V.D. Sorokin ◽  
...  
Keyword(s):  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Coolant Flow

The influence of nozzle deflection on fluid dynamic and infrared characteristics of a two-dimensional convergent–divergent vectoring exhaust system

2019 ◽  
Vol 233 (12) ◽  
pp. 4646-4662
Author(s):  
Hao Wang ◽  
Honghu Ji ◽  
Haohao Lu
Keyword(s):  
Mass Flow ◽  
Infrared Radiation ◽  
Deflection Angle ◽  
Thrust Force ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Exhaust System ◽  
Two Dimensional ◽  
Radiation Characteristics ◽  
Significant Information

Superior maneuverability and good infrared stealthy properties are two key points of the future aircraft. A two-dimensional convergent–divergent (2D-CD) vectoring exhaust system can improve the maneuverability of aircrafts and has been widely applied to the latest generation aircrafts. Understanding fluid dynamic and infrared radiation characteristics of the 2D-CD vectoring exhaust systems under different conditions of the nozzle deflection is very crucial, which can provide significant information for the suppression of the infrared radiation property of the 2D-CD vectoring exhaust system. In this paper, by means of computational fluid dynamics, the fluid dynamic and infrared radiation characteristics of the 2D-CD vectoring exhaust system are studied at subsonic cruise status with nozzle deflection angles from 0 to 20°, and the results are compared with those of the baseline axisymmetric exhaust system. The results indicate that the fluid dynamic performance of a properly designed 2D-CD vectoring exhaust system is equivalent to the fluid dynamic performance of the baseline axisymmetric exhaust system. When the nozzle deflection angle is less than 5°, the mass flow and thrust force of the 2D-CD vectoring exhaust system are almost unchanged, and with the increase of the nozzle deflection angles, the mass flow and thrust force decrease rapidly. The thrust force deflection angles lag behind the nozzle deflection angles all the time, and as the nozzle deflection angle increases, the difference between them decreases. The direction of the maximum infrared radiation of the 2D-CD vectoring exhaust system deflects with the deflection of the nozzle, and the mean integrated infrared radiation intensity of the exhaust system decreases with the increase of nozzle deflection angles.

Effect of an Hourglass-Shape Tapered Sleeve on the Performance of the Fluid Dynamic Bearings of a HDD Spindle Motor

2013 ◽  
Author(s):  
J. H. Lee ◽  
M. H. Lee ◽  
G. H. Jang
Keyword(s):  
Rough Surface ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Rotating Disk ◽  
Groove Depth ◽  
Spindle Motor ◽  
Spindle System ◽  
Thrust Bearings ◽  
Steel Sleeve ◽  
Bearing Ball

Fluid dynamic bearings (FDBs) of a HDD spindle motor support the rotating disk-spindle system through the pressure generated in the fluid lubricant. The radial and axial clearances of a 2.5″ HDD spindle motor are approximately 2 and 30 micro-meters, respectively, and herringbone or spiral grooves are inscribed in the sleeve of journal or thrust bearings to provide pumping pressure. One of the difficult manufacturing processes is to inscribe uniform grooves, especially groove depth in the range of several micro meters. Grooves are inscribed on the surface of the stainless steel sleeve by the electro chemical machining (ECM) which generally generates rough surface of the sleeve in grooved bearing. Ball-sizing process is used to scrape down rough surface. When a ball passes through the sleeve of FDBs to make rough surface smooth, compressive pressure is generated between ball and sleeve inlet and between ball and sleeve outlet, respectively. It forms an hourglass-shape tapered sleeve as shown in Figure 1, and tapered sleeve generally decreases the static and dynamic performance of the FDBs and the HDD spindle system, consequently.

scholarly journals Investigating of Turbine Blades Geometrical Change Effects on Dynamic Performance of IGT-25 Gas Turbine

2019 ◽  
Author(s):  
Nima Zamani Meymian ◽  
Hossein Rabiei
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Turbine Blades ◽  
Gas Generator ◽  
Air Compressor ◽  
Power Turbine ◽  
Geometrical Change

In the paper, the effect of gas generator turbine blades’ geometrical change has been studied on the overall performance of a twin-shaft 25MW gas turbine with industrial application, under dynamic conditions. Geometrical changes include change of thickness and height of gas generator turbine blades which in turn would result in the change in the mass flow rate of passing hot gas, as well as isentropic efficiency in each stage of the turbine. Gas turbine modeling in the paper is zero-dimensional and takes place with consideration of dynamic effects of volume on air compressor components, combustion chamber, gas generator turbine, power turbine, fuel system, as well as effects of heat transfer dynamics between blades, gas path, and effects of operators on inlet guide vanes, fuel valves, and air compressor discharge valve. In the mathematical model of each of the components, steady-state characteristics curves have been used, extracted from 3-Dimensional computational fluid dynamics (CFD). To do so, characteristic curves of the first and second stages of the four-stage turbine have been updated through 3-D fluid dynamic analysis so that the effect of geometrical changes in turbine blades would be applied. Results from effects of these changes on characteristics of transient gas flow including output power of gas generator turbine and power turbine, inlet and outlet temperatures of turbine stages, as well as air and fuel mass flow rates have been provided from the start-ups until reaching the nominal load would be achieved.

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