Experimental Investigation of a Coolant Flow Rate Variation on Knock Tendency in a Small S.I Engine

The modern gas turbine is widely applied in the aviation propulsion and power generation. The rim seal is usually designed at the periphery of the wheel-space and prevented the hot gas ingestion in modern gas turbines. The high sealing effectiveness of rim seal can improve the aerodynamic performance of gas turbines and avoid of the disc overheating. Effect of outer fin axial gap of radial rim seal on the sealing effectiveness and fluid dynamics was numerically investigated in this work. The sealing effectiveness and fluid dynamics of radial rim seal with three different outer fin axial gaps was conducted at different coolant flow rates using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulent model solutions. The accuracy of the presented numerical approach for the prediction of the sealing performance of the turbine rim seal was demonstrated. The obtained results show that the sealing effectiveness of radial rim seal increases with increase of coolant flow rate at the fixed axial outer fin gap. The sealing effectiveness increases with decrease of the axial outer fin gap at the fixed coolant flow rate. Furthermore, at the fixed coolant flow rate, the hot gas ingestion increases with the increase of the axial outer fin gap. This flow behavior intensifies the interaction between the hot gas and coolant flow at the clearance of radial rim seal. The preswirl coefficient in the wheel-space cavity is also illustrated to analyze the flow dynamics of radial rim seal at different axial outer fin gaps.

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Simulation on the Temperature Field of Milling Roller Using Fluent Software

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1095.846 ◽

2015 ◽

Vol 1095 ◽

pp. 846-850

Author(s):

Min Wang ◽

Ke Ping Zhang ◽

Feng Wei Zhang

Keyword(s):

Temperature Field ◽

Flow Rate ◽

Coolant Flow ◽

Coolant Flow Rate ◽

Roller Surface ◽

Fluent Software ◽

The Law

In order to study the law between the internal coolant flow rate and the temperature of milling roller, the temperature field of water-cooled roller was simulated with Fluent software. The results showed that with the increase of the coolant flow rate, the temperature on roller surface decreased, but after the flow rate of coolant increased to 3.5 kg/s, the temperature of roller maintained invariant almost, so 3.5 kg/s was the best flow rate.

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Numerical Studies on the Effect of Tip Clearance and Tip Cooling Flow on Endwall Losses of an Unshrouded Axial Turbine Rotor

ASME 2013 Gas Turbine India Conference ◽

10.1115/gtindia2013-3568 ◽

2013 ◽

Author(s):

K. Asgar Ali ◽

Quamber H. Nagpurwala ◽

Abdul Nassar ◽

S. V. Ramanamurthy

Keyword(s):

Flow Rate ◽

Layer Growth ◽

Coolant Flow ◽

Tip Clearance ◽

Coolant Flow Rate ◽

Total Efficiency ◽

Turbine Stage ◽

Suction Surface ◽

Axial Turbine ◽

Ejection Rate

This paper deals with the numerical investigations on a low pressure axial turbine stage to assess the effect of variation in rotor tip clearance and tip coolant ejection rate on the end wall losses. The rotor, along with the NGV, was modeled to represent the entire turbine stage. The CFX TASCflow software was used to perform steady state analysis for different rotor tip clearances and different tip coolant ejection rates. The locations of the cooling slots were identified on the blade tip and the coolant ejection rate was specified at these areas. The simulations were carried out with tip clearances of 0%, 1% and 2% of blade height and ejection flow rates of 0.5%, 0.75% and 1% of main turbine flow rate. It is shown that the size and strength of the leakage vortex is directly related to the tip clearance. The reduction in efficiency is not in linearity with the tip clearance owing to the effect of boundary layer growth on the end walls. Introduction of the tip coolant flow shows increased total–total efficiency compared to that of the uncooled tip. This is attributed to a reduction in the strength of the leakage vortex due to reduced cross-flow over the tip clearance from pressure surface to suction surface. At a coolant flow rate of 0.75% of the main flow rate, there is significant increase in efficiency of about 0.5%. Optimum tip clearance and coolant flow rate are obtained based on the results of the present analysis.

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Effects of Endwall Film Coolant Flow Rate on Secondary Flows and Coolant Mixing in a First Stage Nozzle Guide Vane

10.1115/1.0003249v ◽

2021 ◽

Author(s):

Mahmood Alqefl ◽

Kedar Nawathe ◽

Pingting Chen ◽

Rui Zhu ◽

Yong Kim ◽

...

Keyword(s):

Flow Rate ◽

Guide Vane ◽

Secondary Flows ◽

Coolant Flow ◽

Coolant Flow Rate ◽

Nozzle Guide Vane ◽

Nozzle Guide

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Analytical Model Quantifying the Net Coolant Flow Rate to a Microstructured Copper Surface validated with Two-Phase PIV Measurements

Journal of Heat Transfer ◽

10.1115/1.4050720 ◽

2021 ◽

Author(s):

Matt Harrison ◽

Joshua Gess

Keyword(s):

Heat Transfer ◽

Analytical Model ◽

Flow Rate ◽

Circular Disk ◽

Nucleate Boiling ◽

High Heat ◽

Heat Fluxes ◽

Coolant Flow ◽

Coolant Flow Rate ◽

Two Phase

Abstract Using Particle Image Velocimetry (PIV), the amount of fluid required to sustain nucleate boiling was quantified to a microstructured copper circular disk. Having prepared the disk with preferential nucleation sites, an analytical model of the net coolant flow rate requirements to a single site has been produced and validated against experimental data. The model assumes that there are three primary phenomena contributing to the coolant flow rate requirements at the boiling surface; radial growth of vapor throughout incipience to departure, bubble rise, and natural convection around the periphery. The total mass flowrate is the sum of these contributing portions. The model accurately predicts the quenching fluid flow rate at low and high heat fluxes with 4% and 30% error of the measured value respectively. For the microstructured surface examined in this study, coolant flow rate requirements ranged from 0.1 to 0.16 kg/sec for a range of heat fluxes from 5.5 to 11.0 W/cm2. Under subcooled conditions, the coolant flow rate requirements plummeted to a nearly negligible value due to domination of transient conduction as the primary heat transfer mechanism at the liquid/vapor/surface interface. PIV and the validated analytical model could be used as a test standard where the amount of coolant the surface needs in relation to its heat transfer coefficient or thermal resistance is a benchmark for the efficacy of a standard surface or boiling enhancement coating/surface structure.

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