Heat Transfer Enhancements at Low-Pressure for Electromechanical Actuators

2021 ◽  
Author(s):  
Jose Juan Corona ◽  
Kamal A. Kaddoura ◽  
John P. Kizito
Keyword(s):  
Heat Transfer ◽  
Low Pressure ◽  
Electromechanical Actuators

Computations of Low Pressure Fluid Flow and Heat Transfer in Ducts Using Direct Simulation Monte Carlo Method

1999 ◽  
Author(s):  
Fang Yan ◽  
Bakhtier Farouk
Keyword(s):  
Heat Transfer ◽  
Monte Carlo ◽  
Noble Gas ◽  
Direct Simulation Monte Carlo ◽  
Low Pressure ◽  
Direct Simulation ◽  
Flow And Heat Transfer ◽  
Gas Transport Properties ◽  
Pressure Profiles ◽  
Simulation Monte Carlo

Abstract High Knudsen (Kn) number flows are found in vacuum and micro-scale systems. Such flows are characterized by non-continuum behavior. For gases, the flows are usually in the slip or transition regimes. In this paper, the direct simulation Monte Carlo (DSMC) method has been applied to compute low pressure, high Kn flow fields in partially heated channels. Computations were carried out for nitrogen, argon, hydrogen, oxygen and noble gas mixtures. Variation of the Kn is obtained by reducing the pressure while keeping the channel width constant. Nonlinear pressure profiles along the channel centerline are observed. Heat transfer from the channel walls is also calculated and compared with the Graetz solution. The effects of varying pressure, inlet flow and gas transport properties (Kn, Reynolds number, Re and the Prandtl number, Pr respectively) on the wall heat transfer (Nu) were examined. A simplified correlation for predicting Nu¯ as a function of Pe¯ and Kn¯ is presented.

Analysis of Temperature Field Based on Hollow Sucker Rod Hot Flushing Technology

2014 ◽  
Vol 1073-1076 ◽  
pp. 2257-2262
Author(s):  
Jie Yu Du ◽  
Jiang Xie ◽  
Yu Qi Zhao ◽  
Li Peng Zhang ◽  
Rui Bin Zhu
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Low Pressure ◽  
Calculation Model ◽  
Simulation System ◽  
Well Production ◽  
Transfer Theory ◽  
Heat Transfer Theory ◽  
Sucker Rod ◽  
Theory Calculation

The hot flushing is a major means of removing wax. For low pressure reservoir, it is possible to produce a large number of washing fluid flowing into the formation, which affects the well production recovery. The application of hollow sucker rod hot flushing technology can avoid fluid pouring back into the formation, and the wells can keep production. Based on the principle of hollow sucker rod hot flushing and heat transfer theory, calculation model of temperature field was established, and hollow sucker rod hot flushing simulation system was developed, which can guide flushing in oilfield.

Heat Transfer Investigation of an Aggressive Intermediate Turbine Duct: Part 1—Experimental Investigation

2010 ◽  
Author(s):  
Carlos Arroyo Osso ◽  
T. Gunnar Johansson ◽  
Fredrik Wallin
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Computational Study ◽  
Convective Heat Transfer Coefficient ◽  
Low Pressure ◽  
Flow Measurements ◽  
Pressure Losses ◽  
Turbofan Engines ◽  
Intermediate Turbine Duct ◽  
Inlet Conditions

In most designs of two-spool turbofan engines, intermediate turbine duct (ITD’s) are used to connect the high-pressure turbine (HPT) with the low-pressure turbine (LPT). Demands for more efficient engines with reduced emissions require more “aggressive ducts”, ducts which provide both a higher radial offset and a larger area ratio in the shortest possible length, while maintaining low pressure losses and avoiding non-uniformities in the outlet flow that might affect the performance of the downstream LPT. The work presented in this paper is part of a more comprehensive experimental and computational study of the flowfield and the heat transfer in an aggressive ITD. The main objectives of the study were to obtain an understanding of the mechanisms governing the heat transfer in ITD’s and to obtain high quality experimental data for the improvement of the CFD-based design tools. This paper consists of two parts. The first one, this one, presents and discusses the results of the experimental study. In the second part, a comparison between the experimental results and a numerical analysis is presented. The duct studied was a state-of-the-art “aggressive” design with nine thick non-turning structural struts. It was tested in a large-scale low-speed experimental facility with a single-stage HPT. In this paper measurements of the steady convective heat transfer coefficient (HTC) distribution on both endwalls and on the strut for the duct design inlet conditions are presented. The heat transfer measurement technique used is based on infrared-thermography. Part of the results of the flow measurements is also included.

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