scholarly journals Critical exponents and transport properties near the QCD critical endpoint from the statistical bootstrap model

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Guruprasad Kadam ◽  
Hiranmaya Mishra ◽  
Marco Panero
Keyword(s):  
Critical Point ◽  
Bulk Viscosity ◽  
Critical Exponents ◽  
Density Ratio ◽  
Hadronic Matter ◽  
Thermodynamic Quantities ◽  
Qcd Critical Point ◽  
Viscosity Coefficients ◽  
Statistical Bootstrap ◽  
Bootstrap Model

AbstractWe present an estimate of the behavior of the shear and bulk viscosity coefficients when the QCD critical point is approached from the hadronic side, describing hadronic matter within the statistical bootstrap model of strong interactions. The bootstrap model shows critical behavior near the quark-hadron transition temperature if the parameter characterizing the degeneracy of Hagedorn states is properly chosen. We calculate the critical exponents and amplitudes of relevant thermodynamic quantities near the QCD critical point and combine them with an Ansatz for the shear and bulk viscosity coefficients to derive the behavior of these coefficients near the critical point. The shear viscosity to entropy density ratio is found to decrease when the temperature is increased, and to approach the Kovtun–Son–Starinets bound $$1/(4\pi )$$ 1 / ( 4 π ) faster near the critical point, while the bulk viscosity coefficient is found to rise very rapidly.

scholarly journals Effects of enhanced bulk viscosity near the QCD critical point

2017 ◽  
Vol 967 ◽  
pp. 816-819 ◽  
Author(s):  
Akihiko Monnai ◽  
Swagato Mukherjee ◽  
Yi Yin
Keyword(s):  
Critical Point ◽  
Bulk Viscosity ◽  
Qcd Critical Point

scholarly journals The critical point of Bootstrap and Lattice QCD

2020 ◽  
Vol 15 ◽  
pp. 233
Author(s):  
N. G. Antoniou ◽  
F. K. Diakonos ◽  
A. S. Kapoyannis
Keyword(s):  
Lattice Qcd ◽  
Critical Point ◽  
High Temperatures ◽  
Chemical Potential ◽  
Hadronic Matter ◽  
Baryon Chemical Potential ◽  
Statistical Bootstrap

It is shown that the hadronic matter formed at high temperatures, according to the prescription of the statistical bootstrap principle, develops a critical point at nonzero baryon chemical potential. The location of the critical point is evaluated with the use of lattice QCD pressure.

Numerical Approach for Real Gas Simulations: Part II — Flow Simulation for Supercritical CO2 Centrifugal Compressor

2017 ◽  
Author(s):  
Swati Saxena ◽  
Ramakrishna Mallina ◽  
Francisco Moraga ◽  
Douglas Hofer
Keyword(s):  
Critical Point ◽  
Centrifugal Compressor ◽  
Supercritical Co2 ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Thermodynamic Quantities ◽  
3D Flow ◽  
Real Gas ◽  
The Real ◽  
Operating Range

This paper is presented in two parts. Part I (Tabular fluid properties for real gas analysis) describes an approach to creating a tabular representation of the equation of state that is applicable to any fluid. This approach is applied to generating an accurate and robust tabular representation of the RefProp CO2 properties. Part II (this paper) presents numerical simulations of a low flow coefficient supercritical CO2 centrifugal compressor developed for a closed loop power cycle. The real gas tables presented in part I are used in these simulations. Three operating conditions are simulated near the CO2 critical point: normal day (85 bar, 35C), hot day (105 bar, 50 C) and cold day (70 bar, 20C) conditions. The compressor is a single stage overhung design with shrouded impeller, 155 mm impeller tip diameter and a vaneless diffuser. An axial variable inlet guide vane (IGV) is used to control the incoming swirl into the impeller. An in-house three-dimensional computational fluid dynamics (CFD) solver named TACOMA is used with real gas tables for the steady flow simulations. The equilibrium thermodynamic modeling is used in this study. The real gas effects are important in the desired impeller operating range. It is observed that both the operating range (minimum and maximum volumetric flow rate) and the pressure ratio across the impeller are dependent on the inlet conditions. The compressor has nearly 25% higher operating range on a hot day as compared to the normal day conditions. A condensation region is observed near the impeller leading edge which grows as the compressor operating point moves towards choke. The impeller chokes near the mid-chord due to lower speed of sound in the liquid-vapor region resulting in a sharp drop near the choke side of the speedline. This behavior is explained by analyzing the 3D flow field within the impeller and thermodynamic quantities along the streamline. The 3D flow analysis for the flow near the critical point provides useful insight for the designers to modify the current compressor design for higher efficiency.

scholarly journals Bootstraping the QCD critical point

2003 ◽  
Vol 563 (3-4) ◽  
pp. 165-172 ◽  
Author(s):  
N.G. Antoniou ◽  
A.S. Kapoyannis
Keyword(s):  
Critical Point ◽  
Qcd Critical Point

scholarly journals Объемная вязкость суспензии наночастиц оксида кремния

2020 ◽  
Vol 46 (12) ◽  
pp. 37
Author(s):  
М.И. Пряжников ◽  
А.В. Минаков
Keyword(s):  
Attenuation Coefficient ◽  
Bulk Viscosity ◽  
Dynamic Viscosity ◽  
Aqueous Suspension ◽  
Sio2 Nanoparticles ◽  
Nanoparticle Concentration ◽  
Viscosity Coefficients ◽  
Wide Range ◽  
First Time ◽  
Mass Concentrations

Data on the bulk viscosity of an aqueous suspension of SiO2 nanoparticles (Ludox TM-50) were obtained using an acoustic spectrometer for the first time. A wide range of mass concentrations of nanoparticles (from 1 to 50 wt.%) was considered. The spectra of the attenuation coefficient of ultrasound and the coefficients of longitudinal and dynamic viscosity were measured. The dependences of the dynamic and bulk viscosity coefficients of the suspensions on the nanoparticle concentration were obtained.

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