On the throttling process of the Kerr-Newman-anti-de Sitter black holes in the extended phase space

TL;DR

This paper systematically analyzes the throttling process of Kerr-Newman-anti-de Sitter black holes in extended phase space, revealing unique thermodynamic behaviors such as the absence of maximum inversion temperatures and the presence of characteristic masses.

Contribution

It provides a comprehensive analytical and numerical study of the Joule-Thomson process in KN-AdS black holes, highlighting new thermodynamic features in extended phase space.

Findings

No maximum inversion temperatures, only minimum ones.

Inversion temperatures are about half of the critical temperatures.

Identification of characteristic masses affecting throttling behavior.

Abstract

The throttling process of the Kerr-Newman-anti-de Sitter (KN-AdS) black holes is systematically studied in the extended phase space. In this framework, the cosmological constant is interpreted as a varying thermodynamic pressure, and the black hole mass is identified with enthalpy. The throttling process is essentially an isenthalpic (i.e., constant-mass) process for the KN-AdS black holes. The Joule-Thomson coefficient, inversion temperature, inversion curve, and isenthalpic curve are investigated in order, with both analytical and numerical methods. It is found that there are no maximum inversion temperatures, but only minimum ones that are around one half of the critical temperatures of the KN-AdS black holes. Two characteristic masses are also discussed to show the detailed features in the throttling behaviors of the KN-AdS black holes.