A Simple Method of Flow Field Diagnosis in Multistage Axial Flow Compressors

ＡＳｉｍｐｌｅＭｅｔｈｏｄｏｆＦｌｏｗＦｉｅｌｄＤｉａｇｎｏｓｉｓｉｎＭｕｌｔｉｓｔａｇｅＡｘｉａｌＦｌｏｗＣｏｍｐｒｅｓｓｏｒｓＪｉｅＬｉｕ；ＤａｊｕｎＹｅ（ＤｅｐａｒｔｍｅｎｔｏｆＴｈｅｒｍａｌＥｎｇｉｎｅｅｒｉｎｇ，ＴｓｉｎｇｈｕａＵｎｉｖｅｒ...     

Analytical and Numerical Study on the Uniformity of Temperature Difference Field in Heat Exchangers

Ａｎａｌｙｔｉｃａｌ　ａｎｄ　Ｎｕｍｅｒｉｃａｌ　Ｓｔｕｄｙ　ｏｎ　ｔｈｅ　Ｕｎｉｆｏｒｍｉｔｙ　ｏｆ　Ｔｅｍｐｅｒａｔｕｒｅ　Ｄｉｆｆｅｒｅｎｃｅ　Ｆｉｅｌｄ　ｉｎ　Ｈｅａｔ　ＥｘｃｈａｎｇｅｒｓＡｎａｌｙｔｉｃａｌａｎｄＮｕｍｅｒｉｃａｌＳｔｕｄ...     

Numerical Simulation of 3—D Temperature Distribution of the Flame Tube of the Combustion Chamber with Air Film COoling

ＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎｏｆ３－ＤＴｅｍｐｅｒａｔｕｒｅＤｉｓｔｒｉｂｕｔｉｏｎｏｆｔｈｅＦｌａｍｅＴｕｂｅｏｆｔｈｅＣｏｍｂｕｓｔｉｏｎＣｈａｍｂｅｒｗｉｔｈＡｉｒＦｉｌｍＣｏｏｌｉｎｇＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎｏｆ３－Ｄ...     

Numerical Simulation of 3—D Turbulent Gas—Particle FLows In a Nonslagging Cyclone COmbustor

ＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎｏｆ３－ＤＴｕｒｂｕｌｅｎｔＧａｓ－ＰａｒｔｉｃｌｅＦｌｏｗｓＩｎａＮｏｎｓｌａｇｇｉｎｇＣｙｃｌｏｎｅＣｏｍｂｕｓｔｏｒ￥ＢｉａｏＺｈｏｕ，ＷｅｎｙｉＬｉｎ，ＬｉｘｉｎｇＺｈｏｕ（ＤｅｐａｒｔｍｅｎｔｏｆＥｎｇ...     

Numerical Simulation of Microgravity Flame Spread Over Solid Combustibles

Ｎｕｍｅｒｉｃａｌ　Ｓｉｍｕｌａｔｉｏｎ　ｏｆ　Ｍｉｃｒｏｇｒａｖｉｔｙ　Ｆｌａｍｅ　Ｓｐｒｅａｄ　Ｏｖｅｒ　Ｓｏｌｉｄ　ＣｏｍｂｕｓｔｉｂｌｅｓＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎｏｆＭｉｃｒｏｇｒａｖｉｔｙＦｌａｍｅＳｐｒｅａｄＯｖｅｒＳｏｌｉ...     

Flow Field Calculations for Afterburner

Ｆｌｏｗ　Ｆｉｅｌｄ　Ｃａｌｃｕｌａｔｉｏｎｓ　ｆｏｒ　ＡｆｔｅｒｂｕｒｎｅｒＦｌｏｗＦｉｅｌｄＣａｌｃｕｌａｔｉｏｎｓｆｏｒＡｆｔｅｒｂｕｒｎｅｒ￥ＺｈａｏＪｉａｎｘｉｎｇ；ＬｉｕＱｕａｎｚｈｏｎｇ；ＬｉｕＨｏｎｇ（ＮａｎｊｉｎｇＵｎｉｖｅｒｓｉｔ...     

Vortex Simulation of Axisymmetrical Flows in Cylindrical Geometries．PartI：Numerical Algorithm

ＶｏｒｔｅｘＳｉｍｕｌａｔｉｏｎｏｆＡｘｉｓｙｍｍｅｔｒｉｃａｌＦｌｏｗｓｉｎＣｙｌｉｎｄｒｉｃａｌＧｅｏｍｅｔｒｉｅｓ．ＰａｒｔＩ：ＮｕｍｅｒｉｃａｌＡｌｇｏｒｉｔｈｍ￥ＡｎｄｒＧｉｏｖａｎｎｉｎｉ（ＵｎｉｖｅｒｓｉｔｅＰａｕｌＳａｂａｔｉｅｒａｎ...     

A Numerical Model Prediction for Boiling Multi Channel Flow Rate Distribution andApplication in 600MW Supercritical Variable－Pressure Once－Through Boiler with Vertical Tube Coils

ＡＮｕｍｅｒｉｃａｌＭｏｄｅｌＰｒｅｄｉｃｔｉｏｎｆｏｒＢｏｉｌｉｎｇＭｕｌｔｉＣｈａｎｎｅｌＦｌｏｗＲａｔｅＤｉｓｔｒｉｂｕｔｉｏｎａｎｄＡｐｐｌｉｃａｔｉｏｎｉｎ６００ＭＷＳｕｐｅｒｃｒｉｔｉｃａｌＶａｒｉａｂｌｅ－ＰｒｅｓｓｕｒｅＯｎｃｅ－Ｔｈ...     

A Numerical Analysis of the Forced Convection Condensation of Saturated Vapor Flowing Axially Outside a Horizontal Tube

ＡＮｕｍｅｒｉｃａｌＡｎａｌｙｓｉｓｏｆｔｈｅＦｏｒｃｅｄＣｏｎｖｅｃｔｉｏｎＣｏｎｄｅｎｓａｔｉｏｎｏｆＳａｔｕｒａｔｅｄＶａｐｏｒＦｌｏｗｉｎｇＡｘｉａｌｌｙＯｕｔｓｉｄｅａＨｏｒｉｚｏｎｔａｌＴｕｂｅ￥ＷｅｉｚｈｏｎｇＬｉ，ＷｅｉｃｈｅｎｇＷａ...     

Numerical Calculation of 3—D TUrbulent Flow in Curvilinear Coordinate Systems with Nostaggered Grids

ＮｕｍｅｒｉｃａｌＣａｌｃｕｌａｔｉｏｎｏｆ３－ＤＴｕｒｂｕｌｅｎｔＦｌｏｗｉｎＣｕｒｖｉｌｉｎｅａｒＣｏｏｒｄｉｎａｔｅＳｙｓｔｅｍｓｗｉｔｈＮｏｎｓｔａｇｇｅｒｅｄＧｒｉｄｓＺｈａｎｇＪｉｎｇｚｈｏｕ；ＬｉＬｉｇｕｏ；ＷｕＧｕｏｃｈｕａｎ（Ｎａｍ...     

基于深度学习的汽水分离再热数字孪生系统故障诊断研究

针对汽水分离再热系统等复杂工业系统,为解决传统故障诊断模型准确率受限于故障样本稀缺和故障数据时间维度与变量维度耦合的问题,提出一种基于深度学习的故障诊断方法。首先,构建汽水分离再热数字孪生系统,用以建立故障诊断数据仓库,解决数据样本层面稀缺性的问题。其次,进一步构建基于深度残差网络的故障诊断模型,用以诊断汽水分离再热系统典型故障,包括流量不均、破口、传热恶化和阀门特性变化,从而解决数据变量层面时变、多维度的问题。结果表明：数字孪生系统能够实现汽水分离再热系统稳态、动态和故障工况的精确仿真,满足后续深度学习模型的数据需求;基于深度残差网络的故障诊断模型能够实现时变、多维工业数据的故障诊断;采用T分布随机邻域嵌入(TSNE)方法对模型可视化,可对不同故障类型的数据进行明显区分。     

ADINA软件在土石坝渗流场计算中的应用

根据基本方程及定解条件的比较分析,将AD INA软件的温度场模块分析功能应用于渗流场的分析,并采用死活单元技术,通过迭代算法计算自由水面位置(浸润线),解决了实际工程观音岩心墙土石坝渗流稳定问题的求解。该方法可以解决复杂边界、多种介质的渗流问题,为实际工程设计应用提供强有力的途径。     

Chemical reaction,heat and mass transfer on MHD flow over a vertical stretching surface with heat source and thermal stratification effects

An analysis has been carried out to obtain the nonlinear MHD flow with heat and mass transfer characteristics of an incompressible, viscous, electrically conducting and Boussinesq fluid on a vertical stretching surface with chemical reaction and thermal stratification effects. An approximate numerical solution for the flow problem has been obtained by solving the governing equations using numerical technique. A magnetic field is applied transversely to the direction of the flow. Adopting the similarity transformation, governing nonlinear partial differential equations of the problem are transformed to nonlinear ordinary differential equations. Then the numerical solution of the problem is derived using Gill method, for different values of the dimensionless parameters. The results obtained show that the flow field is influenced appreciably by the presence of thermal stratification, chemical reaction and magnetic field.     

Magnetized squeezed flow of time‐dependent Prandtl‐Eyring fluid past a sensor surface

The present numerical investigation describes the influence of a transverse magnetic field on the heat and mass transfer characteristics of time‐dependent squeezed flow of Prandtl‐Eyring fluid past a horizontal sensor surface. The current physical problem is modeled based on the considered flow configuration. Also, the present problem is analyzed under the influence of Lorentz forces, to explore the impact of a magnetic field on the flow behaviour. The considered physical problem in the present study gives highly nonlinear coupled time‐dependent, two‐dimensional partial differential equations. The governing flow equations are reduced to the system of nonlinear ordinary differential equations by imposing the suitable similarity transformations on the laws of motion. Due to the inadequacy in the analytical methods, the present problem is solved by using the Runge‐Kutta fourth order integration scheme with shooting method. The flow and heat transfer behaviour of various control parameters are studied and presented in terms of graphs and tables. From the current investigation it is noticed that, the increasing magnetic parameter enhances the velocity field and diminishes the temperature profile in the flow region. Also, the magnifying permeable velocity parameter decreases the temperature field. The present similarity solutions are found to be in good agreement with previously published results.     

On the control of solidification using magnetic fields and magnetic field gradients

Solidification from the melt to near net shape is a commonly used manufacturing technique. The fluid flow patterns in the melt affect the quality of the final product. By controlling the flow behavior, the final solidified material can be suitably affected. Most of the magnetic field approaches to melt flow control rely on the application of a constant magnetic field. A constant magnetic field results in the Lorentz force which is used to damp and control the flow. However, simultaneous application of a magnetic gradient results in the Kelvin force along with the Lorentz force. This can be used for better control of the melt flow resulting in higher crystal quality. In the present work, a computational method for the design of solidification of a conducting material is addressed. The control parameter in the design problem is the time history of the imposed magnetic field. A steady, constant magnetic gradient is also maintained during the process. The design problem is posed as an unconstrained optimization problem. The adjoint method for the inverse design of continuum processes is adopted. Examples of designing the time history of the imposed magnetic field for the directional growth of various materials are presented to demonstrate the developed formulation.     

Inverse Natural Convection Problem with Radiation in Rectangular Enclosure

Inverse thermal problem is applied to natural convective flow with radiative heat transfer. The bottom wall temperature in the 2-D cavity domain is estimated by using gas temperature measurements in the flow field. The inverse problem is solved through a minimization of an objective function using the conjugate gradient method with adjoint problem. The effects of functional form of bottom wall temperature profile, the number and the position of measurement points, and the measurement errors are investigated and discussed. The conjugate gradient method is found to work well in estimating the bottom wall temperature, even when natural convection with radiation phenomena is involved.     

AN ACCURATE METHOD FOR THE SIMULATION OF THREE-DIMENSIONAL INCOMPRESSIBLE HEATED PIPE FLOW

A numerical scheme using Fourier expansions in the streamwise and azimuthal directions and Jacobi polynomials in the radial direction for the direct numerical simulation of three-dimensional incompressible pipe flow with heating is presented. The proposed basis and test functions for the thermal field in conjunction with those for the velocity field set forth by Leonard and Wary offer an accurate representation of flow variables in transitional flow. A simple test to a linear stability problem demonstrates that this method yields very accurate results with relatively few radial modes and is well suited for the simulation of nonisothermal pipe flow transition.     

An inverse heat transfer problem for restoring the temperature field in a polymer melt flow through a narrow channel

An important problem in polymer processing is to provide suitable thermal conditions for polymer melt flows through narrow channels during extrusion or injection. Due to various thermal effects (e.g., viscous dissipation, chemical reactions) the temperature profile of the melt could be quite sharp. In order to numerically simulate polymer flows and heat transfer through a narrow channel, the inlet boundary conditions, which are generally unknown, have to be specified. For such a creeping flow, the area where the velocity field develops is very short. In contrast, the inlet temperature profile develops quite slowly and affects the temperature field far downstream. An approach is suggested for restoring the inlet temperature profile by solving an inverse heat transfer problem using Cauchy data at the channel wall. The polymer flow is assumed to be a steady, laminar and incompressible flow of a non-Newtonian pseudo-plastic fluid, which is governed by the Navier–Stokes equations and a constitutive “power law” model for viscosity. This non-linear inverse problem is solved by a sequential approximation method combined with Tikhonov's regularization method. Notably, this approach has been found to be efficient for field observation problems, when the magnitude of non-linearity is not too large. The results of numerical simulation are presented and questions regarding accuracy are discussed.     

Mathematical modelling of non-isothermal silica transport and deposition in a porous medium

The problem of transport and deposition of silica in non-isothermal flows, either in a porous medium or a single fracture, is investigated. Analytic solutions are obtained using the method of characteristics for both the one-dimensional problem of constant rate injection into a channel or packed column and the radially symmetric problem of the flow away from a reinjection well. Silica deposition is represented by a first order rate equation. Studies on the temperature effects of reinjection into a hot or cold reservoir are undertaken using the one-dimensional model. The strong dependence of the rate of silica deposition on temperature is confirmed by the model. The radial flow model is applied to some field data from the Otake geothermal field, Japan. The model produces a good match to the permeability decline observed in the wells. Mathematical models of silica deposition resulting from non-isothermal flow in a single fracture are successfully tested against some previously reported numerical results.