scholarly journals Heat Transfer Coefficient and Flow Characteristics of Hot Steel Plate Cooling by Multiple Inclined Impinging Jets

2016 ◽  
Vol 56 (12) ◽  
pp. 2236-2242 ◽  
Author(s):  
Qian Xie ◽  
Bingxing Wang ◽  
Zhaodong Wang ◽  
Guodong Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Steel Plate ◽  
Flow Characteristics ◽  
Impinging Jets

scholarly journals Local Heat Transfer Coefficient and Adiabatic Wall Temperature Measurement Beneath Arrays of Staggered and Inline Impinging Jets

1994 ◽  
Author(s):  
Kenneth W. Van Treuren ◽  
Zuolan Wang ◽  
Peter T. Ireland ◽  
Terry V. Jones ◽  
S. T. Kohler
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Wall Temperature ◽  
Impinging Jets ◽  
Hole Diameter ◽  
Channel Height ◽  
Published Data ◽  
Target Plate ◽  
Adiabatic Wall

Recent work, Van Treuren et al. (1993), has shown the transient method of measuring heat transfer under an array of impinging jets allows the determination of local values of adiabatic wall temperature and heat transfer coefficient over the complete surface of the target plate. Using this technique, an inline array of impinging jets has been tested over a range of average jet Reynolds numbers (10,000–40,000) and for three channel height to jet hole diameter ratios (1, 2, and 4). The array is confined on three sides and spent flow is allowed to exit in one direction. Local values are averaged and compared with previously published data in related geometries. The current data for a staggered array is compared to those from an inline array with the same hole diameter and pitch for an average jet Reynolds number of 10,000 and channel height to diameter ratio of one. A comparison is made between intensity and hue techniques for measuring stagnation point and local distributions of heat transfer. The influence of the temperature of the impingement plate through which the coolant gas flows on the target plate heat transfer has been quantified.

Heat Transfer Enhancement by Turbulent Impinging Jets

2000 ◽  
Author(s):  
M. Kumagai ◽  
R. S. Amano ◽  
M. K. Jensen
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Stokes Equations ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Impinging Jets ◽  
Transfer Model ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Abstract A numerical and experimental investigation on cooling of a solid surface was performed by studying the behavior of an impinging jet onto a fixed flat target. The local heat transfer coefficient distributions on a plate with a constant heat flux were computationally investigated with a normally impinging axisymmetric jet for nozzle diameter of 4.6mm at H/d = 4 and 10, with the Reynolds numbers of 10,000 and 40,000. The two-dimensional cylindrical Navier-Stokes equations were solved using a two-equation k-ε turbulence model. The finite-volume differencing scheme was used to solve the thermal and flow fields. The predicted heat transfer coefficients were compared with experimental measurements. A universal function based on the wave equation was developed and applied to the heat transfer model to improve calculated local heat transfer coefficients for short nozzle-to-plate distance (H/d = 4). The differences between H/d = 4 and 10 due to the correlation among heat transfer coefficient, kinetic energy and pressure were investigated for the impingement region. Predictions by the present model show good agreement with the experimental data.

Some Generalizations in Compressible Flow Characteristics

1973 ◽  
Vol 95 (2) ◽  
pp. 65-74
Author(s):  
R. P. Benedict
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Compressible Flow ◽  
Flow Characteristics ◽  
Loss Coefficient ◽  
All Solutions

Certain generalizations in compressible flow characteristics are first reviewed including specific solutions to flow with losses in the absence of heat transfer (i.e., Fanno flow), in terms of an empirical loss coefficient, Kf. The analysis is then extended to specific solutions to flow with heat transfer, with and without losses (i.e., isothermal and Rayleigh flows), in terms of an empirical heat transfer coefficient, Kq. All solutions are mapped on generalized plots which, in addition to their utility, exhibit a certain beauty of symmetry and continuity.

scholarly journals Estimation of Heat Transfer Coefficient and Flow Characteristics on Heat Transfer Tube in Sodium-Water Reaction

2011 ◽  
Vol 48 (3) ◽  
pp. 315-321 ◽  
Author(s):  
Toshinori MATSUMOTO ◽  
Takashi TAKATA ◽  
Akira YAMAGUCHI ◽  
Akikazu KURIHARA ◽  
Hiroyuki OHSHIMA
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flow Characteristics ◽  
Heat Transfer Tube ◽  
Transfer Tube

scholarly journals Conjugate Heat Transfer Study at Interior Surface of NGV Leading Edge with Combined Shower Head and Impingement Cooling

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Arun Kumar Pujari ◽  
B. V. S. S. S. Prasad ◽  
N. Sitaram
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Conjugate Heat Transfer ◽  
Computational Study ◽  
Guide Vane ◽  
Internal Heat ◽  
Leading Edge ◽  
Impinging Jets ◽  
Mainstream Flow

A computational study on conjugate heat transfer is carried out to present the behavior of nondimensional temperature and heat transfer coefficient of a Nozzle Guide Vane (NGV) leading edge. Reynolds number of both mainstream flow and coolant impinging jets are varied. The NGV has five rows of film cooling holes arranged in shower head manner and four rows of impingement holes arranged in staggered manner. The results are presented by considering materials of different thermal conductivity. The results show that the mainstream flow affects the temperature distribution on the interior side of the vane leading edge for high conductivity material whereas it has negligible effects for low conductivity material. The effect of changing blowing ratio on internal heat transfer coefficient and internal surface temperature is also presented.

scholarly journals Modeling Film-Coolant Flow Characteristics at the Exit of Shower-Head Holes

2000 ◽  
Author(s):  
Vijay K. Garg
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Coolant Flow ◽  
The Heat Transfer Coefficient

Abstract The coolant flow characteristics at the hole exits of a film-cooled blade are derived from an earlier analysis where the hole pipes and coolant plenum were also discretized. The blade chosen is the VKI rotor with three staggered rows of shower-head holes. The present analysis applies these flow characteristics at the shower-head hole exits. A multi-block three-dimensional Navier-Stokes code with Wilcox’s k-ω model is used to compute the heat transfer coefficient on the film-cooled turbine blade. A reasonably good comparison with the experimental data as well as with the more complete earlier analysis where the hole pipes and coolant plenum were also gridded is obtained. If the 1/7th power law is assumed for the coolant flow characteristics at the hole exits, considerable differences in the heat transfer coefficient on the blade surface, specially in the leading-edge region, are observed even though the span-averaged values of h match well with the experimental data. This calls for span-resolved experimental data near film-cooling holes on a blade for better validation of the code.

scholarly journals The analysis of thermal and flow characteristics of the condensation of refrigerant zeotropic mixtures in minichannels

2016 ◽  
Vol 37 (2) ◽  
pp. 41-69 ◽  
Author(s):  
Tadeusz Bohdal ◽  
Katarzyna Widomska ◽  
Małgorzata Sikora
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Flow Characteristics ◽  
Internal Diameter ◽  
Test Results ◽  
Experimental Heat ◽  
Experimental Heat Transfer ◽  
Calculation Results

Abstract The paper presents the results of experimental heat transfer and pressure drop during condensation of the single component refrigerant R134a and zeotropic mixtures R404A, R407C, and R410A in tube minichannels of internal diameter from the range 0.31-3.30 mm. The local values and the average of heat transfer coefficient and pressure drop in the whole range of the change in mass quality were measured. On the basis of the obtained test results there was illustrated the influence of the change of mass vapor quality, the mass flux density, and the inner diameter of channel on the studied parameters. These results were compared with the calculation results based on the relations postulated by other authors. The discrepancy range was ± 50%. On the basis of given test results own correlation was developed to calculate the heat transfer coefficient and pressure drop of tested refrigerants which presents the obtained results in a range of discrepancy of ±25%.

Local Heat Transfer Coefficient Distribution With Air Impingement Into a Cavity

1972 ◽  
Author(s):  
F. Burggraf
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Impinging Jets ◽  
Local Heat Transfer Coefficient ◽  
Cavity Surface ◽  
Transfer Coefficients ◽  
Coefficient Distribution

Impingement heat transfer coefficients are presented for a row of holes impinging into an oval cavity with the spent air leaving through holes on one or both sides of the cavity. The distribution around the cavity surface is obtained and is correlated with a survey of the recent literature. In addition, local heat flux gages were used with an impingement jet air supply which could be changed in location along the axis of the test section. This permitted the determination of local heat transfer coefficient distribution over the surface both around the cavity and also in the region between the impinging jets. This two-dimensional distribution is shown to be influenced by the bleed geometry and the shape of the impinging jet holes.

scholarly journals Experimental Estimation of the Heat Transfer Coefficient of an Unglazed Solar Plate for Unsteady Humid Outdoor Condition

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Felix Uba ◽  
Eric Osei Essandoh ◽  
Gilbert Ayine Akolgo ◽  
Richard Opoku ◽  
Lawrence Oppong-Kyereh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Mild Steel ◽  
Transfer Coefficient ◽  
Specific Heat ◽  
Steel Plate ◽  
Outdoor Environment ◽  
Empirical Equations ◽  
Outdoor Condition ◽  
The Heat Transfer Coefficient

This research presents a study on the heat transfer coefficient for an unglazed solar plate collector in an unsteady humid outdoor environment. The purpose for undertaking this research is to investigate the correlation between the heat transfer coefficient and air speed and also verify whether heat transfer from unglazed solar thermal collectors under outdoor conditions can be experimentally determined using a particular mathematical relationship for different locations. In estimating the heat transfer coefficient for an unglazed solar plate in an unsteady humid outdoor condition, an experiment was held using an outdoor setup that measured temperatures, wind speeds, and solar radiations from 11:00 A.M. to 2:00 P.M. The solar plate collector was placed on a flat bed of height 2.2 m and a collection area of 0743 m2. An average temperature of 45°C was recorded for a mild steel plate collector which was initially exposed to an ambient temperature which ranges from 25°C to 32°C. The interfacial temperature between the plate and an asbestos board ranges from 42°C to 52°C, and that of the asbestos and a plywood is 40°C to 46°C. The specific heat capacity of the mild steel plate and the asbestos board used for the construction of the experimental setup are 25.00 kJ/kg and 950.00 kJ/kg, respectively, while the thermal conductivity of these materials is 0.46 W/m·K and 0.25 W/m·K, respectively. The novelty of this work is the use of such a study to generate empirical equations for Ghana and to produce representative equations for determining the heat transfer coefficient for solar plate collectors in unsteady humid outdoor conditions in West Africa. This work is expected to contribute data alongside similar works done for different areas to help propose empirical equations for estimating global and not site-specific heat transfer coefficients.

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