Conjugate Heat Transfer Analysis on Generic Rim Seal Configurations in Rotor-Stator System

2018 ◽  
Author(s):  
Xingyun Jia ◽  
Liguo Wang ◽  
Qun Zheng ◽  
Hai Zhang ◽  
Yuting Jiang
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Analysis ◽  
Minimum Mass ◽  
Aerodynamic Efficiency ◽  
Axial Clearance ◽  
The Impact

Performance of generic rim seal configurations, axial-clearance rim seal (ACS), radial-clearance rim seal (RCS), radial-axial clearance rim seal (RACS) are compared under realistic working conditions. Conjugate heat transfer analysis on rim seal is performed in this paper to understand the impact of ingestion on disc temperature. Results show that seal effectiveness and cooling effectiveness of RACS are the best when compared with ACS and RCS, the minimum mass flow rate for seal of RACS is 75% of that of RCS, and 34.6% of ACS. Authors compare the disc temperature distribution between different generic rim seal configurations where the RACS seems to be favorable in terms of low disc temperature. In addition, RACS has higher air-cooled aerodynamic efficiency, minimizing the mainstream performance penalty when compared with ACS and RCS. Corresponding to the respective minimum mass flow rate for seal, the air-cooled aerodynamic efficiency of RACS is 23.71% higher than that of ACS, and 12.79% higher than the RCS.

scholarly journals A Critical Review on Thermo-Hydraulic Performance of Wire Screen Matrix Packed Solar Air Heaters

2021 ◽  
Author(s):  
Prashant Verma ◽  
Abhishek Saxena ◽  
L. Varshney
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Hydraulic Performance ◽  
Major Influence ◽  
Pumping Power ◽  
Bed Porosity ◽  
Wire Screen ◽  
The Impact

Solar air heaters (SAHs) have an important role in applications such as space heating and industrial drying worldwide. The packing of SAH bed not only increases the heat transfer area but also increases the pumping power losses thereby limiting the thermo-hydraulic performance. In the present study, efforts have been made for a critical assessment of the literature dealing with the impact of collector bed and operating parameters over thermal and thermo-hydraulic performance for different configurations of wire screen matrix packed SAH. The porosity of bed and mass flow rate of the air have a major influence on the thermo-hydraulic performance of wire screen matrix packed SAH. It is found that the enhancement in the volumetric heat transfer coefficient due to a decrease in bed porosity is obtained at the expense of increase in pumping power which ultimately affects the thermo-hydraulic performance of wire screen matrix packed SAH. In general it is observed that porosity is an important parameter that affects the thermo-hydraulic performance. It is seen that matrix having porosity 0.937 yields thermo-hydraulic performance of 68% at mass flow rate 0.023 kg/s where as for the same mass flow rate porosity of 0.887 results thermo-hydraulic performance of only 42%.

scholarly journals Computational Fluid Dynamics Analysis of Flow Patterns, Pressure Drop, and Heat Transfer Coefficient in Staggered and Inline Shell-Tube Heat Exchangers

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shubham Sharma ◽  
Shalab Sharma ◽  
Mandeep Singh ◽  
Parampreet Singh ◽  
Rasmeet Singh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Heat Transfer Analysis ◽  
Staggered Grid ◽  
Shell Side ◽  
Shell And Tube

In this numerical study, the heat transfer performance of shell-and-tube heat exchangers (STHXs) has been compared for two different tube arrangements. STHX having 21 and 24 tubes arranged in the inline and staggered grid has been considered for heat transfer analysis. Shell-and-tube heat exchanger with staggered grid arrangement has been observed to provide lesser thermal stratification as compared to the inline arrangement. Further, the study of variation in the mass flow rate of shell-side fluid having constant tube-side flow rate has been conducted for staggered grid structure STHX. The mass flow rate for the shell side has been varied from 0.1 kg/s to 0.5 kg/s, respectively, keeping the tube-side mass flow rate as constant at 0.25 kg/s. The influence of bulk mass-influx transfer rate on heat transfer efficiency, effectiveness, and pressure drop of shell-tube heat exchangers has been analyzed. CFD results were compared with analytical solutions, and it shows a good agreement between them. It has been observed that pressure drop is minimum for the flow rate of 0.1 kg/s, and outlet temperatures at the shell side and tube side have been predicted to be 40.94°C and 63.63°C, respectively.

scholarly journals Thermodynamic performance evaluation of an air-air heat pipe heat exchanger

2014 ◽  
Vol 18 (4) ◽  
pp. 1343-1353 ◽  
Author(s):  
Mohan Kumar ◽  
S.C. Kaushik ◽  
S.N. Garg
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Pipes ◽  
Heat Transfer Analysis ◽  
Thermodynamic Performance ◽  
Pipe Heat

In this paper, heat transfer analysis for an air-air heat exchanger was experimentally carried out to find its thermal performance and effectiveness. Air-air heat exchanger equipped with finned heat pipes was considered for the experimentation. Mass flow rate of air was considered in between 0.24 to 0.53 [kg/sec]. The temperature at the condenser side of the heat pipe heat exchanger was kept constant at around 23 [?C] and at the evaporator part it was varied from 88 to 147 [?C]. The performance of heat pipe heat exchanger was evaluated at different mass flow rate of air, in terms of effectiveness and compared with its corresponding value found by theoretical analysis.

Numerical Study of a Linear Cascade With Upstream Cavity Using Various Rim-Seal Geometries and Purge Rates

2018 ◽  
Author(s):  
Maxime Fiore ◽  
Nicolas Gourdain ◽  
Jean-François Boussuge ◽  
Eric Lippinois
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Numerical Study ◽  
Suction Side ◽  
High Fidelity ◽  
Linear Cascade ◽  
Axial Clearance ◽  
Secondary Air ◽  
The Impact

This paper introduces numerical investigation of a low-speed linear cascade rig with upstream cavity at Reynolds number commonly observed in modern low-pressure turbine stage. This configuration was tested experimentally during the EU project MAGPI (2007–2011) focused on the impact of secondary air systems on gas turbine performance. Three different purge mass flow rate have been tested numerically using three different rim-seal geometry (axial clearance, simple and double radial overlap). The mechanisms and influence of these two parameters on loss generation for the main annulus flow is investigated. The ability of high-fidelity numerical methods to deal with such kind of configuration is assessed by comparing several unsteady codes over the axial geometry at three purge mass flow rate available. Two Large-Eddy Simulation (LES) solvers based respectively on structured and unstructured meshes and a LES-LBM approach in which equations discretization is based upon a Lattice-Boltzmann Method (LBM) and a Sub-Grid Scale (SGS) model from LES developments are used. The comparison against MAGPI experiments and previous Reynolds Averaged Navier-Stokes (RANS) simulation show that despite a variety of flow dynamics modelling, discretization and numerical parameters, the different unsteady codes are well able to recover aerodynamic quantities into the mainstream passage in which purge flow blows at various rate and different rim-seal geometry. Further results obtained from such high-fidelity methods exhibit strong interaction of separated hub boundary at rim-seal interface with nonuniform pressure field imposed by downstream blade leading to a strong in-depth of mainstream flow into the cavity for the axial clearance. Simple and double overlap damper this phenomenon due to localized recirculation zone into the rim-seal. In addition, hub passage vortex and blade suction side unsteadiness are shown to be strongly related to the vortex shedding process occurring at rim-seal interface.

Effusion Cooling With Backside Crossflow Cooling and the Backside Coolant Mass Flow Rate Greater Than the Effusion Cooling Mass Flow

2013 ◽  
Author(s):  
G. E. Andrews ◽  
I. M. Khalifa
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Conjugate Heat Transfer ◽  
Cross Flow ◽  
Leading Edge ◽  
Duct Flow ◽  
Low Velocity ◽  
Mean Velocity

Full coverage effusion cooling was studied for a square array of 90° effusion cooling holes with backside cooling using a 5 mm depth duct air supply to the coolant holes, with the duct air mass flow rate being greater than the effusion cooling flow. This geometry represents combustor primary zone wall cooling with the dilution air or main combustion air comprising the excess backside flow rate. Active cooling was used with metal walls and 300K effusion cooling into a 27 m/s mean velocity duct flow at 770K crossflow temperature. The aim was to provide conjugate heat transfer experimental data to validate conjugate heat transfer CFD prediction procedures. The 152 mm square test section had 15 rows of holes The X/D value studied was 11.0, which gives a 3% effusion wall pressure loss at a relatively low effusion coolant mass flow rate. The duct air feed to the holes enhanced the backside cooling of the wall. These results were compared with previous work using a plenum chamber air feed and with a crossflow duct, but with equal cross flow air to effusion air. The increased duct air feed velocity relative to the plenum low velocity air feed resulted in an increase in the overall cooling effectiveness due to the additional heat transfer by the duct crossflow velocity. This effect was across the whole duct length when there was surplus cross flow air relative to effusion air, without this the enhanced heat transfer was small and confined to the leading edge area.

Effect of pre-swirl nozzle closure modes on unsteady flow and heat transfer characteristics in a pre-swirl system of aero-engine

2021 ◽  
pp. 095441002110191
Author(s):  
Gaowen Liu ◽  
Zhao Lei ◽  
Aqiang Lin ◽  
Qing Feng ◽  
Yan Chen
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Drop ◽  
Thermodynamic Characteristics ◽  
Circumferential Direction ◽  
Temperature Changes ◽  
Air Supply ◽  
Cooling Air

The pre-swirl system is of great importance for temperature drop and cooling air supply. This study aims to investigate the influencing mechanism of heat transfer, nonuniform thermodynamic characteristics, and cooling air supply sensitivity in a pre-swirl system by the application of the flow control method of the pre-swirl nozzle. A novel test rig was proposed to actively control the supplied cooling air mass flow rate by three adjustable pre-swirl nozzles. Then, the transient problem of the pre-swirl system was numerically conducted by comparison with 60°, 120°, and 180° rotating disk cavity cases, which were verified with the experiment results. Results show that the partial nozzle closure will aggravate the fluctuation of air supply mass flow rate and temperature. When three parts of nozzles are closed evenly at 120° in the circumferential direction, the maximum value of the nonuniformity coefficient of air supply mass flow rate changes to 3.1% and that of temperature changes to 0.25%. When six parts of nozzles are closed evenly at 60° in the circumferential direction, the maximum nonuniformity coefficient of air supply mass flow rate changes to 1.4% and that of temperature changes to 0.20%. However, different partial nozzle closure modes have little effect on the average air supply parameters. Closing 14.3% of the nozzle area will reduce the air supply mass flow rate by 9.9% and the average air supply temperature by about 1 K.

Heat Transfer and Flow Friction Characteristics for Compact Cold Plates

2003 ◽  
Vol 125 (1) ◽  
pp. 104-113 ◽  
Author(s):  
Chang-Yuan Liu ◽  
Ying-Huei Hung
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Nusselt Number ◽  
Thermal Resistance ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Average Nusselt Number ◽  
Cold Plate ◽  
Air Mass

Both experimental and theoretical investigations on the heat transfer and flow friction characteristics of compact cold plates have been performed. From the results, the local and average temperature rises on the cold plate surface increase with increasing chip heat flux or decreasing air mass flow rate. Besides, the effect of chip heat flux on the thermal resistance of cold plate is insignificant; while the thermal resistance of cold plate decreases with increasing air mass flow rate. Three empirical correlations of thermal resistance in terms of air mass flow rate with a power of −0.228 are presented. As for average Nusselt number, the effect of chip heat flux on the average Nusselt number is insignificant; while the average Nusselt number of the cold plate increases with increasing Reynolds number. An empirical relationship between Nu¯cp and Re can be correlated. In the flow frictional aspect, the overall pressure drop of the cold plate increases with increasing air mass flow rate; while it is insignificantly affected by chip heat flux. An empirical correlation of the overall pressure drop in terms of air mass flow rate with a power of 1.265 is presented. Finally, both heat transfer performance factor “j” and pumping power factor “f” decrease with increasing Reynolds number in a power of 0.805; while they are independent of chip heat flux. The Colburn analogy can be adequately employed in the study.

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