Experimental and numerical investigations on a high-density polyethylene (HDPE) blown film cooling with a new design of the counter-flow/radial jet air-ring

2021 ◽  
pp. 875608792110260
Author(s):  
ME Ismail ◽  
MM Awad ◽  
AM Hamed ◽  
MY Abdelaal ◽  
EB Zeidan
Keyword(s):  
Heat Transfer ◽  
Numerical Simulations ◽  
Film Cooling ◽  
Radiation Heat Transfer ◽  
Absolute Error ◽  
Numerical Results ◽  
Upper Lip ◽  
Original Design ◽  
Blown Film ◽  
Set Up

This study experimentally and numerically investigates a typical HDPE blown film production process cooled via a single-lip air-ring. The processing observations are considered for the proposed subsequent modifications on the air-ring design and the location relative to the die to generate a radial jet, directly impinging on the bubble. Measurements are performed to collect the actual operating parameters to set up the numerical simulations. The radiation heat transfer and the polymer phase change are considered in the numerical simulations. The velocity profile at the air-ring upper-lip is measured via a five-hole Pitot tube to compare with the numerical results. The comparison between the measurements and the numerical results showed that the simulations with the STD [Formula: see text] turbulence model are more accurate with a minimum relative absolute error (RAE) of 1.6%. The numerical results indicate that the peak Heat Transfer Coefficient (HTC) at the impingement point for the modified design with radial jet and longer upper-lip is 29.1% higher than the original design at the same conditions. Besides, increasing the air-ring upper-lip height increased the averaged HTC, which is 13.4% higher than the original design.

scholarly journals Conjugate Heat Transfer Characteristics in a Highly Thermally Loaded Film Cooling Configuration with TBC in Syngas

Aerospace ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 16
Author(s):  
Jing Ren ◽  
Xueying Li ◽  
Hongde Jiang
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Transfer Model ◽  
Plate Temperature ◽  
Total Percentage ◽  
Barrier Coating

Future power equipment tends to take hydrogen or middle/low heat-value syngas as fuel for low emission. The heat transfer of a film-cooled turbine blade shall be influenced more by radiation. Its characteristic of conjugate heat transfer is studied experimentally and numerically in the paper by considering radiation heat transfer, multicomposition gas, and thermal barrier coating (TBC). The Weighted Sum of Gray Gases Spectral Model and the Discrete Transfer Model are utilized to solve the radiative heat transfer in the multicomposition field, while validated against the experimental data for the studied cases. It is shown that the plate temperature increases significantly when considering the radiation and the temperature gradient of the film-cooled plate becomes less significant. It is also shown that increasing percentage of steam in gas composition results in increased temperature on the film-cooled plate. The normalized temperature of the film-cooled plate decreases about 0.02, as the total percentage of steam in hot gas increases 7%. As for the TBC effect, it can smooth out the temperature distribution and insulate the heat to a greater extent when the radiative heat transfer becomes significant.

Numerical Simulation of Process Parameters in Flexible Discrete Clamp Stretch Forming

2012 ◽  
Vol 161 ◽  
pp. 53-57 ◽  
Author(s):  
He Li Peng ◽  
Ming Zhe Li ◽  
Peng Xiao Feng
Keyword(s):  
Numerical Simulation ◽  
Friction Coefficient ◽  
Numerical Simulations ◽  
Process Parameters ◽  
Numerical Results ◽  
Fe Model ◽  
Stretch Forming ◽  
Set Up

Flexible DCSF technology was put forward, and its forming character was described. The flexible DCSF machine was developed and related stretching experiment were carried out. The experimental photos show the DCSF technology is feasible and the DCSF machine is practicable. The FE model of flexible DCSF was set up, and extensive numerical simulations for spherical parts, saddle parts and S-type parts were carried out by Abaqus. The numerical results show that the longer the transitional length is, the more homogeneous the stretching strain and the thickness become. The smaller the friction coefficient is, the more homogeneous the stretching strain and the thickness become. The larger the clamp number is, the better the fit degree becomes. This work may provide useful guidance on the flexible DCSF process.

Modeling Heat Transfer of the Air Gap between Human Body and Clothing

2011 ◽  
Vol 332-334 ◽  
pp. 1611-1614
Author(s):  
Ying Ke ◽  
Yun Yi Wang ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Numerical Model ◽  
Human Skin ◽  
Human Body ◽  
Air Gap ◽  
Numerical Results ◽  
Unsteady State ◽  
State Heat ◽  
Set Up

An unsteady-state heat transfer numerical model of the microclimate between human skin and clothing is set up. Air-gap thickness less than 17mm is considered. Matlab pde toolbox is chosen to compute the numerical model. The numerical results of the model agrees well with a set of published experimental data.

Conjugate Heat Transfer Characteristics of a Highly Thermal-Loaded Film Cooling System in Hot and Multi-Composition Gas Condition

2014 ◽  
Author(s):  
Mingfei Li ◽  
Jing Ren ◽  
Hongde Jiang
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Radiation Effects ◽  
Conjugate Heat Transfer ◽  
Cooling System ◽  
Radiation Heat Transfer ◽  
Numerical Data ◽  
Gas Composition ◽  
Higher Temperature ◽  
Zero Emission

To reach the goal of Zero-Emission or Near-Zero-Emission, the future advanced power equipment would be using hydrogen or middle/low heat-value syngas as fuel. Radiation would be more important in turbine heat transfer due to the higher temperature and multi-composition gas. The main goal of current study is analyzing the characteristic of conjugate heat transfer considering radiation heat transfer, multi-composition gas, with and without TBC coated. To study the conjugate heat transfer mechanism including conduction/ convection/ radiation in the film cooling flow field considering the effect of the gas composition, both the experimental and the numerical studies are carried out in the present work. By comparing the experimental and the numerical data, it is concluded that the implemented thermal conduction/ convection/ radiation simulation method is valid for the cases studied. The results show that higher percentage of steam in gas composition leads to the higher temperature (lower normalized temperature) on the plate. With the total percentage of steam in hot gas increasing per 7%, the normalized temperature on the plate decrease about 0.02. The heat insulation effect of TBC is more obvious when the radiation effects are strong. TBC makes the temperature distribution more uniform to some extent.

The Parameters Identification Method of Radiation Heat Transfer for Nanoporous Materials

2013 ◽  
Vol 631-632 ◽  
pp. 341-347
Author(s):  
Ji Jun Yu ◽  
Fei Huang ◽  
Gui Qing Jiang
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Nanoporous Materials ◽  
Parameters Identification ◽  
Approximation Model ◽  
Identification Method ◽  
Flux Approximation ◽  
Flux Model ◽  
Identification Theory ◽  
Set Up

The two flux approximation model is usually used to calculate the heat transfer of radiation for porous materials. In this paper, the parameters identification method of the extinction coefficient and the albedo of scattering in the two flux model is set up by using the identification theory according to the data of the back temperature. The simulated process shows that the convergence rate is fast and the results by the parameters identification are very close to the origin values.

Influence of Different Rim Widths and Blowing Ratios on Film Cooling Characteristics for a Blade Tip

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Jin Wang ◽  
Bengt Sundén ◽  
Min Zeng ◽  
Qiu-wang Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulations ◽  
Film Cooling ◽  
Three Dimensional ◽  
Suction Side ◽  
Leakage Flow ◽  
Pressure Side ◽  
Tip Leakage Flow ◽  
Blade Tip ◽  
Film Cooling Holes

Three-dimensional simulations of the squealer tip on the GE-E3 blade with eight film cooling holes were carried out. The effect of the rim width and the blowing ratio on the blade tip flow and cooling performance were revealed. Numerical simulations were performed to predict the leakage flow and the tip heat transfer with the k–ɛ model. For the squealer tip, the depth of the cavity is fixed but the rim width varies to form a wide cavity, which can decrease the coolant momentum and the tip leakage flow velocity. This cavity contributes to the improvement of the cooling effect in the tip zone. To investigate the influence on the tip heat transfer by the rim width, numerical simulations were performed as a two-part study: (1) unequal rim width study on the pressure side and the suction side and (2) equal rim width study with rim widths of 0.58%, 1.16%, and 1.74% of the axial chord (0.5 mm, 1 mm, and 1.5 mm, respectively) on both the pressure side rim and the suction side rim. With different rim widths, the effect of different global blowing ratios, i.e., M = 0.5, 1.0 and 1.5, was investigated. It is found that the total heat transfer rate is increasing and the heat transfer rates on the rim surface (RS) rapidly ascend with increasing rim width.

Squealer Tip Heat Transfer With Film Cooling

2010 ◽  
Author(s):  
Sumanta Acharya ◽  
Gregory Kramer ◽  
Louis Moreaux ◽  
Chiyuki Nakamata
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Leading Edge ◽  
Numerical Results ◽  
Transfer Coefficients ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Heat Transfer Coefficients ◽  
Pressure Distributions

Heat transfer coefficients and film cooling effectiveness values were obtained numerically on a film cooled 2-D gas turbine blade tip model featuring a cutback squealer. In addition, pressure distributions were obtained at 50% and 98% spans. The calculations were performed for a single blade with periodic boundary conditions imposed along the two mid-passage boundaries formed by the adjacent blades. The calculations were performed with the realizable k-ε turbulence model and non-equilibrium wall function using 1.1 million elements. The numerical results are obtained for 4 blowing ratios and for Reynolds number based on axial chord and inlet velocity of 75,000. Limited experimental measurements of the blade pressure distributions and the uncooled tip heat transfer coefficients were performed for validation of the numerical results. The experiments were conducted in a six-blade low-speed wind tunnel cascade at a Reynolds number of 75,000. The heat transfer experiment involved a transient infrared thermography technique. Experimental heat transfer coefficients were extracted using a transient technique. The predicted pressure distributions agree very well with the measurements while the heat transfer coefficient predictions show qualitative agreement. From the numerical results, it can be seen that as the blowing ratio is increased, larger regions of film cooling effectiveness were seen with higher effectiveness values between the camber line and suction side. Heat transfer coefficients were largest near the leading edge for all cases.

Numerical Simulation of the HDR Blowdown Experiment V31.1 at Karlsruhe

2002 ◽  
Author(s):  
Lars Andersson ◽  
Per Andersson ◽  
Jan Lundwall ◽  
Jan Sundqvist ◽  
Pascal Veber
Keyword(s):  
Numerical Simulation ◽  
Computer Program ◽  
Numerical Simulations ◽  
Pressure Vessel ◽  
Reactor Vessel ◽  
Numerical Results ◽  
Local Pressure ◽  
Structure Interaction ◽  
Set Up ◽  
Reactor Pressure

This paper presents a comparison between experimental results and numerical simulations of a reactor pressure vessel internals response due to a rapid depressurization associated to a pipe break. The experiment is designed to fulfil conditions relative to a Pressurised Water Reactor (PWR). The numerical simulation is performed with the computer program package ADINA. The calculations are performed both with and without Fluid Structure Interaction (FSI) effects. It is shown that FSI effects are very important for this problem. The comparison between experimental and numerical results is performed for local pressure in the water and displacements and strains in the reactor vessel and internals. Our experience is that good numerical results can be achieved for this type of loading for all compared quantities. Note that the experiment was set up to show the importance of FSI-phenomena, the effect of this could then be stronger in the experiment compared to a “real” case.

Investigations of Heat Transfer and Film Cooling Effect on a Worn Squealer Tip

2020 ◽  
Author(s):  
Mingliang Ye ◽  
Xin Yan
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Pressure Loss ◽  
Total Pressure ◽  
Total Pressure Loss ◽  
Wear Depth ◽  
Original Design ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Cavity Floor

Abstract Wear damage commonly occurs in modern gas turbine rotor blade tip due to relative movements and expansions between rotating and stationary parts. Tip wear has a significant impact on the aerodynamic, heat transfer and cooling performance of rotor blades, thus threatening the economy and safety of whole gas turbine system. Based on a simple linear wear model, this paper numerically investigates the aerodynamic, heat transfer and film cooling performance of a worn squealer tip with three starting-locations of wear (sl = 25%Cax, 50%Cax and 75%Cax) and five wear-depths (wd = 0.82%, 1.64%, 2.46%, 3.28% and 4.10%). Firstly, based on the existing experimental data, numerical methods and grid independence are examined carefully. Then, three dimensional flow fields, total pressure loss distributions, heat transfer coefficients and film cooling effectiveness in worn squealer tip region are computed, which are compared with the original design case. The results show that, with the increase of wear depth and the movement of wear starting-location to the leading edge, the scale and intensity of cavity vortex are increased, which results in the extended high heat transfer area on cavity floor near the leading edge. Wear makes more coolant flow out of the cavity, and reduces the area-averaged film cooling effectiveness at the bottom of cavity, but increases the film cooling effectiveness on pressure-side rim. The increase of wear depth makes more flow leak through the tip gap, thus increasing the scale and intensity of leakage vortex and further increasing the total pressure loss in the tip gap. Compared with the original design case, as the wear depth is increased from 0.82% to 4.10%, the mass-averaged total pressure loss in cascade is increased by 0.3–6.7%, the area-averaged heat transfer coefficient on cavity floor is increased by 1.7–29.1% while on squealer rim it is decreased by 3.1–26.3%, and the area-averaged film cooling effectiveness on cavity floor is decreased by 0.035 at most while on squealer rim it is increased by 0.064 at most.

scholarly journals Conjugate Heat Transfer Characteristics in a Highly Thermally Loaded Film Cooling Configuration with TBC in Syngas

2018 ◽  
Author(s):  
Jing Ren ◽  
Xueying Li ◽  
Hongde Jiang
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Transfer Model ◽  
Plate Temperature ◽  
Total Percentage ◽  
Heat Value

The future power equipment tends to take hydrogen or middle/low heat-value syngas as fuel for low emission. The heat transfer of film cooled turbine blade shall be influenced more by radiation. Its characteristic of conjugate heat transfer is studied experimentally and numerically in the paper by considering radiation heat transfer, multi-composition gas and TBC. The Weighted Sum of Gray Gases spectral model and Discrete Transfer Model are utilized to solve the radiative heat transfer in the multi-composition field, while validated against the experimental data for the studied cases. It is shown that the plate temperature increases significantly when considering the radiation and the temperature gradient of the film cooled plate becomes larger. It is also shown that increasing percentage of steam in gas composition results in increased temperature on the film-cooled plate. The normalized temperature of the film-cooled plate decreases about 0.02, as the total percentage of steam in hot gas increases per 7%. As for the TBC effect, it can smooth out the the temperature distribution and insulate the heat to a greater extent when the radiative heat transfer becomes significant.

Sign in / Sign up

Export Citation Format

Share Document