Experimental Investigation of Subcooled Flashing Flow in Simulated Cracks

2011 ◽  
Author(s):  
Brian Wolf ◽  
Shripad T. Revankar ◽  
Jovica R. Riznic
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Flow Rate ◽  
Test Specimen ◽  
Room Temperature ◽  
Flow Characteristics ◽  
Test Facility ◽  
Experimental Program ◽  
Flow Discharge ◽  
Subcooled Water

In this study an experimental program was developed to measure the choking flow rate of subcooled water through simulated tube crack geometries (L/D<10 L< 5mm) and results are compared with models in literature. A test facility was designed and built to measure leak rates of subcooled water from through-wall simulated tube cracks up to 6.8 MPa. Two types of test specimens were used in the experimental program. One, a round orifice like hole is created to simulate a pitting type flaw. The others are laser cut slits representing axial cracks. Flow discharge tests were carried out with water at room temperature to determine the flow characteristics for each test specimen. Also, subcooled flashing discharge tests with heated water were carried out up to a vessel pressure of 6.8 MPa at various subcoolings. A modified Burnell correlation was developed using upstream saturation and subcooled temperature conditions and the predictions of the correlation agreed well with the present experimental data.

Experimental Investigation of Effect of Tip Coolant Ejection on Internal Flow Characteristics Within a Realistic Blade Coolant Channel

2013 ◽  
Author(s):  
Jian Pu ◽  
Zhaoqing Ke ◽  
Jianhua Wang ◽  
Lei Wang ◽  
Hongde You
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Turbine Blade ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Flow Ratio ◽  
Lp Turbine ◽  
Mass Flow Ratio

This paper presents an experimental investigation on the characteristics of the fluid flow within an entire coolant channel of a low pressure (LP) turbine blade. The serpentine channel, which keeps realistic blade geometry, consists of three passes connected by a 180° sharp bend and a semi-round bend, 2 tip exits and 25 trailing edge exits. The mean velocity fields within several typical cross sections were captured using a particle image velocimetry (PIV) system. Pressure and flow rate at each exit were determined through the measurements of local static pressure and volume flow rate. To optimize the design of LP turbine blade coolant channels, the effect of tip ejection ratio (ER) from 180° sharp bend on the flow characteristics in the coolant channel were experimentally investigated at a series of inlet Reynolds numbers from 25,000 to 50,000. A complex flow pattern, which is different from the previous investigations conducted by a simplified square or rectangular two-pass U-channel, is exhibited from the PIV results. This experimental investigation indicated that: a) in the main flow direction, the regions of separation bubble and flow impingement increase in size with a decrease of the ER; b) the shape, intensity and position of the secondary vortices are changed by the ER; c) the mass flow ratio of each exit to inlet is not sensitive to the inlet Reynolds number; d) the increase of the ER reduces the mass flow ratio through each trailing edge exit to the extent of about 23–28% of the ER = 0 reference under the condition that the tip exit located at 180° bend is full open; e) the pressure drop through the entire coolant channel decreases with an increase in the ER and inlet Reynolds number, and a reduction about 35–40% of the non-dimensional pressure drop is observed at different inlet Reynolds numbers, under the condition that the tip exit located at 180° bend is full open.

scholarly journals Experimental Investigation of a Rectangular Airlift Pump

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
I. I. Esen
Keyword(s):  
Experimental Investigation ◽  
Cross Section ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Rectangular Cross Section ◽  
Hydraulic Performance ◽  
Experimental Program ◽  
Empirical Equations ◽  
Airlift Pump

Hydraulic performance of an airlift pump having a rectangular cross-section 20 mm × 80 mm was investigated through an experimental program. The pump was operated at six different submergence ratios and the liquid flow rate was measured at various flowrates of air injected. The effectiveness of the pump, defined as the ratio of the mass of liquid pumped to the mass of air injected, was determined as a function of the mass of air injected for different submergence ratios. Results obtained were compared with those for circular airlift pumps using an analytical model for circular pumps. Effectiveness of the rectangular airlift pump was observed to be comparable to that of the circular pumps. Hydraulic performance of the rectangular airlift pump investigated was then described by a set of semilogarithmic empirical equations.

An Experimental Study of the Flow of R-407C in an Adiabatic Spiral Capillary Tube

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
M. K. Mittal ◽  
R. Kumar ◽  
A. Gupta
Keyword(s):  
Experimental Data ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Tube ◽  
Flow Characteristics ◽  
Flow Rates ◽  
Tube Test ◽  
Mass Flow Rates ◽  
R 134A

The objective of this study is to investigate the effect of coiling on the flow characteristics of R-407C in an adiabatic spiral capillary tube. The characteristic coiling parameter for a spiral capillary tube is the coil pitch; hence, the effect of the coil pitch on the mass flow rate of R-407C was studied on several capillary tube test sections. It was observed that the coiling of the capillary tube significantly reduced the mass flow rate of R-407C in the adiabatic spiral capillary tube. In order to quantify the effect of coiling, the experiments were also conducted for straight a capillary tube, and it was observed that the coiling of the capillary tube reduced the mass flow rate in the spiral tube in the range of 9–18% as compared with that in the straight capillary tube. A generalized nondimensional correlation for the prediction of the mass flow rates of various refrigerants was developed for the straight capillary tube on the basis of the experimental data of R-407C of the present study, and the data of R-134a, R-22, and R-410A measured by other researchers. Additionally, a refrigerant-specific correlation for the spiral capillary was also proposed on the basis of the experimental data of R-407C of the present study.

Experimental Investigation of Nitrogen Flow in Long Microtubes

2009 ◽  
Author(s):  
Chengwen Li ◽  
Li Jia ◽  
Tiantian Zhang ◽  
Xing Li
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Flow Characteristics ◽  
Nitrogen Flow ◽  
Current Experiment ◽  
Turbulent Region ◽  
Compressibility Effect ◽  
Friction Factors ◽  
Macro Scale ◽  
Predicted Values

Nitrogen flow characteristics in Polyetheretherketone microtubes with inner diameters (D) ranging from 0.255mm to 0.553mm were experimentally investigated. It is indicated that most of the experimental points in laminar region are coincided with the conventional theoretical predicted value, but several plots caused by instrumental errors are lower than predicted values at small Re. In turbulent region, the friction factors for D = 0.255mm microtubes with L = 0.800m and 1.591m are slightly lower than conventional values; the experimental data for D = 0.553mm microtube with L = 0.800m is lower than that in D = 0.255mm pipes. The entrance effect obviously influences friction factor even if the L/D of microtubes is more than 60, where it can always be neglected in macro-scale. Due to the enhancement of compressibility effect as diameter decrease (Kn increase), friction constant is larger in smaller-size microtubes. The transition Reynolds number in current experiment (except for L = 0.200mm and D = 0.553mm) ranges from1600–2000, while a little early transition phenomenon is found in L = 0.200m, D = 0.553mm tube.

Conjugate Heat Transfer Modeling of a Film-Cooled, Flat-Plate Test Specimen in a Gas Turbine Aerothermal Test Facility

2013 ◽  
Author(s):  
T. G. Sidwell ◽  
S. A. Lawson ◽  
D. L. Straub ◽  
K. H. Casleton ◽  
S. Beer
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Gas Turbine ◽  
Turbulence Model ◽  
Film Cooling ◽  
Test Specimen ◽  
Conjugate Heat Transfer ◽  
Test Facility ◽  
Plate Test ◽  
Mesh Density

The aerothermal test facility at the National Energy Technology Laboratory (NETL) provides experimental data at realistic gas turbine conditions to enable the development of advanced film cooling strategies for future gas turbine components. To complement ongoing experimental studies, Fluent computational fluid dynamics (CFD) models have been developed to provide a framework for comparison of cooling strategies and to provide fundamental understanding of the fluid dynamic and conjugate heat transfer (CHT) processes occurring in the experiments. The results of a parametric study of the effects of mesh density, near-wall refinement, wall treatment, turbulence model and gradient discretization order on the CHT predictions are presented, and the simulation results are compared to experimental data. A flat plate test specimen with a single row of laidback fan-shaped film cooling holes was modeled at a process pressure of 3 bar, a process gas flow rate (m) of 0.325 kg/s (Re ≈ 100,000) and a blowing ratio (M) of 2.75. Three polyhedral mesh cases and three turbulence models (Realizable k-ε, SST k-ω and RSM Stress-ω) were implemented with enhanced wall treatment (EWT) and 1st-order and 2nd-order gradient discretization. The results show that the choice of turbulence model will have little effect on the results when utilizing the finest mesh case and 2nd-order discretization. It was also shown that the SST k-ω turbulence model cases showed minimal mesh sensitivity with 2nd-order discretization, while the Re k-ε turbulence model cases were more sensitive to mesh density and near-wall refinement. The results thus indicate that the SST k-ω turbulence model can predict the convective heat transfer adequately with a relatively coarse mesh, which will save computational resources for later inclusion of radiative heat transfer effects to provide comprehensive CHT predictions.

Experimental Measurements of an Air Conditioner Performance

2002 ◽  
Author(s):  
Luis Rosario ◽  
Muhammad M. Rahman ◽  
Jose L. F. Porteiro
Keyword(s):  
Experimental Data ◽  
Air Conditioning ◽  
Experimental Studies ◽  
Operating Conditions ◽  
System Capacity ◽  
Coefficient Of Performance ◽  
Test Facility ◽  
Experimental Program ◽  
Air Conditioner ◽  
Test Unit

The performance of the air conditioner was tested in an extensive experimental program using the environmentally controlled chambers in a test facility. Two psychometric rooms provided constant ambient temperature and humidity conditions for a test unit using ASHRAE standard procedures [1]. The indoor and outdoor units were placed into separate environmental chambers, which provided precise temperature, humidity, and airflow conditions for simulation of various operating conditions. The first goal of the experimental program was to define the range of conditions over which the test unit should be tested. The second goal of the experimental studies was to determine the performance of the test unit under the defined conditions. All air conditioner performance data has been collected with air side instrumentation only. Experimental tests were performed using the test unit over a range of outdoor temperatures between 22.4°C (80°F) and 40.6°C (105°F) and indoor temperatures between 18.3°C (65°F) and 35°C (95°F). Analysis of the experimental data was performed by studying air conditioning parameters such as heat rejection rate qc, compressor power W, system capacity qe, and coefficient of performance COP. The analysis was accomplished with the variation of a boundary condition. The sensitivity analysis of experimental data gave expected results when compared to those shown by air conditioning units similar to our test unit.

scholarly journals Experimental Investigation of Convection Heat Transfer in High Pressure and High Temperature Gas Flows

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Francisco I. Valentín ◽  
Ryan Anderson ◽  
Masahiro Kawaji
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Experimental Investigation ◽  
Convection Heat Transfer ◽  
Simulation Models ◽  
Vertical Tube ◽  
Flow Channel ◽  
Test Facility ◽  
Convection Heat ◽  
Heater Power

This work focuses on an experimental investigation of convection heat transfer to a gas in a vertical tube under strongly heated conditions at high temperatures and pressures up to 943 K and 65 bar. A unique test facility for convection heat transfer experiments has been constructed, and used to obtain experimental data useful for better understanding and validation of numerical simulation models. This test facility consists of a single flow channel in a 2.7 m long, 0.11 m diameter graphite column with four 2.3 kW heaters placed symmetrically around the 16.8 mm diameter flow channel. Upward flow convection experiments with air and nitrogen were conducted for inlet Reynolds numbers from 1300 to 60,000, thus covering laminar, transition, and fully turbulent flow regimes. Experiments were performed at different flow rates (3.8 × 10−4 to 1.5 × 10−2 kg/s) and heater power up to 6 kW. Importantly, the data analysis considered the thermophysical properties of the gas and graphite changing with temperature and pressure. Nusselt number results are further compared to existing correlations. The effect of pressure and heater power on degraded heat transfer is examined. The analyses of the experimental data showed significant reductions in Reynolds number of up to 50% and Nusselt numbers of up to 90% between the gas inlet and outlet.

scholarly journals Experimental measurements of gravity casting flow

2019 ◽  
Vol 213 ◽  
pp. 02054
Author(s):  
Libor Lobovský ◽  
Tomáš Mandys
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Experimental Investigation ◽  
Physical Properties ◽  
Room Temperature ◽  
Optical Measurement ◽  
Measurement Methods ◽  
Experimental Measurements ◽  
Transparent Material ◽  
Gravity Casting

An experimental investigation of casting processes performed under well controlled laboratory conditions is presented. Casting molds made of transparent material allow for analysis of flow patterns by means of standard optical measurement methods. The tests are carried out for selected highly-viscous Newtonian fluids at room temperature. The physical properties of the test fluids (i.e. viscosity, surface tension and density) are identified. As a result, an extensive set of experimental data is provided.

Validation of RELAP5/MOD3.4 for Flashing-Induced Instabilities in a Natural Circulation Loop

2020 ◽  
Author(s):  
Yifan Xu ◽  
Minjun Peng ◽  
Genglei Xia ◽  
Yanan Zhao
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Flow Instability ◽  
Natural Circulation ◽  
Density Wave ◽  
System Stability ◽  
Test Facility ◽  
Circulation System ◽  
Inlet Temperature ◽  
Relap5 Code

Abstract This paper aims to validate the effectiveness of the widely used Relap5 code in simulating two-phase natural circulation, and its capability to predict flashing-induced instabilities. The RELAP5 code is validated against experimental data from the NMR test facility, which was designed to investigate the flow instability for a BWR-type novel modular reactor (NMR). The simulations by RELAP5/MOD3.4 code had been performed under various conditions by changing system pressure, core inlet subcooling, core inlet flow resistance, and core heat power etc. The flow stability for a certain operating condition could be determined from the time trace profile of the loop natural circulation flow rate. The results showed that the simulated mass flow rate increased with increasing core inlet temperature, reproducing the experimental trend. And the maximum error between the experimental data and the calculated results is within 10%. The predicted natural circulation dimensionless numbers, the phase change number and inlet subcooling number, also had a good agreement with the experimental data. In general, the RELAP5 code is able to simulate flashing-induced instability and density wave oscillations, which occurred in the natural circulation test facility at low pressures. However, flashing tends to be suppressed at a higher pressure (400kPa). And the enlargement of core inlet resistance coefficient can also have a positive impact on natural circulation system stability.

An Experimental Investigation of the Shell-Side Pressure Drop of Enlarged-Hole Whole-Rounded Baffle Heat Exchanger

2010 ◽  
Vol 160-162 ◽  
pp. 1622-1627 ◽  
Author(s):  
Hai Yang Sun ◽  
Cai Fu Qian
Keyword(s):  
Experimental Investigation ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Flow Characteristics ◽  
Shell Side ◽  
Pressure Drops ◽  
Side Pressure

In this paper, the flow characteristics of the whole-rounded enlarged-hole baffle heat exchangers are experimentally studied with the stress on the shell-side pressure drops. It is found that the shell-side pressure drops for the whole-rounded baffles with the enlarged holes are greatly decreased. Compared with the square layout, the enlarged-hole whole-rounded baffles in the case of triangle layout is even more effective in decreasing the pressure drop. The shell-side pressure drops for the heat exchangers with the enlarged-hole whole-rounded baffles are proportional to the square of the flow rate.

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