Modified entropy correction formula for the Roe scheme

Kermani, M.J.; Plett, E. G.

doi:10.2514/6.2001-83

Cited by 38 publications

(31 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Also, is the eigenvalue of the ux Jacobian matrix determined at Roe's averaged condition [32]. The numerical ux using Roe scheme is obtained from the following formulae:…”

Section: Spatial Discretizationmentioning

confidence: 99%

Effects of non-equilibrium condensation on aerodynamics of the flow field in a steam turbine cascade

Esfe¹,

Kermani²,

Saffar‐Avval³

2017

Scientia Iranica

View full text Add to dashboard Cite

Abstract. In the present paper, an in-house CFD code is developed using Roe scheme to simulate a condensing two-phase ow in blade to blade passage of a steam turbine. E ects of condensation on the ow eld of steam turbine rotor tip section are investigated for di erent outlet pressures. Firstly, comparison is performed between results of wet and dry cases. Then, e ects of outlet pressure variations on the ow eld are studied. Finally, e ects of condensation on di erent speci cations of the ow eld (total pressure loss coe cient, entropy generation, and deviation angle) are investigated. Also, the mechanism of ow deviation in the cascade ow eld is described. Condensation has a great in uence on the behavior of the ow eld based on the numerical results of this paper. It changes the out ow direction, and consequently the ow entering to the next blade deviates from its on-design condition; thus, additional losses are produced. For example, the value of deviation angle reaches 7:62 for wet case and exit Mach number M e = 1:45. Also, there are stagnation pressure loss and entropy generation due to non-equilibrium condensation that reduce the e ciency of the steam turbine.

show abstract

“…Also, is the eigenvalue of the ux Jacobian matrix determined at Roe's averaged condition [32]. The numerical ux using Roe scheme is obtained from the following formulae:…”

Section: Spatial Discretizationmentioning

confidence: 99%

Effects of non-equilibrium condensation on aerodynamics of the flow field in a steam turbine cascade

Esfe¹,

Kermani²,

Saffar‐Avval³

2017

Scientia Iranica

View full text Add to dashboard Cite

show abstract

“…To avoid expansion shocks from appearing we use a previously developed algorithm which given by Kermani and Plett (2001).…”

Section: Time and Space Discretizationmentioning

confidence: 99%

Numerical Study of Water Production from Compressible Moist-Air Flow

Hamidi

Kermani

2016

JAFM

View full text Add to dashboard Cite

In this research a numerical study of water production from compressible moist-air flow by condensing of the vapor component of the atmospheric air through a converging-diverging nozzle is performed. The atmospheric air can be sucked by a vacuum compressor. The geographical conditions represent a hot and humid region, for example Bandar Abbas, Iran, with coordinates, 27 0 11 ' N and 56 0 16 ' E and summer climate conditions of about 40℃and relative humidity above 80%. Parametric studies are performed for the atmospheric-air temperature between, 40℃ to 50℃, and relative humidity between49.6% to 100.%. For these ranges of operating conditions and a nozzle with the area ratio of 1.17, the liquid mass flow rates falls in the range 0.272 to 0.376 kg/s. The results show that, the energy consumed by the compressor for production 1 kg of water will be 1.279 kWh. The price of 1 kWh is 372 Rials, therefore the price for the production of 1 kg liquid water will be 475.8 Rials, therefore, the scheme is economically suitable.

show abstract

“…The Roe scheme gives non-physical expansion shocks in the regions where the eigenvalues of the Jacobian matrix vanish, e.g., the sonic regions and the stagnation points. To obtain a physical solution under the abovementioned conditions, an entropy correction formula from Kermani and Plett (2001b) is used.…”

Section: Solver Descriptionmentioning

confidence: 99%

Improvement of a solution of inviscid compressible flows using a mixed wall boundary condition

Madadi

Kermani

Khazaei

2015

Engineering Applications of Computational Fluid Mechanics

View full text Add to dashboard Cite

Boundary conditions have a vital role in the numerical solution of the partial differential equations governing fluid flows, and they have a great influence over the numerical stability and accuracy of the final solutions. One of the most important physical boundary conditions in flow field analysis, especially for inviscid flows, is the wall boundary condition imposed on body surfaces. To solve a three-dimensional compressible Euler equation (with five PDE's), a total of five boundary conditions on the body surface should be prescribed. The wall's velocity magnitude is one of the parameters to be determined, and the way this velocity magnitude is calculated affects the accuracy and stability of the numerical approach. In this paper, four different methods for calculation of the wall velocity magnitude are introduced, tested and compared against several test cases of subsonic and supersonic flows. Since there are many problems where both subsonic and supersonic flows coexist, a mixed boundary condition takes into account the flow Mach number is proposed. The mixed boundary condition is applied to several test cases and the stability of the method is examined.

show abstract

Modified entropy correction formula for the Roe scheme

Cited by 38 publications

References 3 publications

Effects of non-equilibrium condensation on aerodynamics of the flow field in a steam turbine cascade

Effects of non-equilibrium condensation on aerodynamics of the flow field in a steam turbine cascade

Numerical Study of Water Production from Compressible Moist-Air Flow

Improvement of a solution of inviscid compressible flows using a mixed wall boundary condition

Contact Info

Product

Resources

About