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We consider a model for thermal contact through a diathermal interface between two macroscopic bodies at different temperatures: an Ising spin chain with nearest neighbor interactions is endowed with a Glauber dynamics with different temperatures and kinetic parameters on alternating sites. The inhomogeneity of the kinetic parameter is a novelty with respect to the model of Ref.[1] and we exhibit its influence upon the stationary non equilibrium values of the two-spin correlations at any distance. By mapping to the dynamics of spin domain walls and using free fermion techniques, we determine the scaled generating function for the cumulants of the exchanged heat amounts per unit of time in the long time limit., 20 pages

Much attention has been paid to study the state of charge (SOC) during fast filling process. However, investigation on identifying the foremost factors and contribution of them to the filling mass is still an open issue. In essence, the contributing factors are multiple, of which, the most important factors can be found out by thermodynamical analysis. Based on the thermodynamical analysis and mass flow rate balance, some equations calculating filling mass and heat transfer are outstanding. The mass filling rate, the initial pressure in the cylinder and the inlet temperature of hydrogen are confirmed to be the utmost important factors influencing the filling mass. A computational fluid dynamics (CFD) model is established. The simulation results show the liner or inverse proportional relationship between filling mass and the three factors, hence, a formula for the final mass with diverse filling conditions is figured out. By means of studying the state of charge obtained by adiabatic and diathermal filling processes, a formula to investigate the heat transfer is proposed. Both the filling mass and heat transfer are coupled with the three factors. Therefore, the effect of heat transfer on filling mass has been investigated. It seems that the filling mass is dependent on the total heat transfer during fast filling.

Nonadiabatic one-dimensional flow of steam in elementary modules of pipe networks, i.e. straight pipes and fittings, has been considered. A simple method of determining the amount of condensed water, distributions of pressure and temperature along these modules has been developed. The problem of critical flow regime has been discussed and a general formula of checking for the presence of sonic velocities at arbitrary cross section of the pipeline has been given. When embedded into a supervising procedure, the described routines can be used to build a mathematical model of a steam pipe network of arbitrary topology. Numerical examples are included. A set of equations describing all the steam properties used in the calculations is given in the Appendix.

The compact thermodynamic approach to the systems containing calcium, magnesium, and carbonate species is referred to dissolution of dolomite, as an example of nonequilibrium ternary salt when introduced into aqueous media. The study of dolomite is based on all attainable physicochemical knowledge, involved in expressions for equilibrium constants, where the species of the system are interrelated. The species are also involved in charge and concentration balances, considered as constraints put on a closed system, separated from the environment by diathermal walls. The inferences are gained from calculations performed with use of an iterative computer program. The simulated quasistatic processes occurred under isothermal conditions, started at a preassumed pH0 value of the solution where dolomite was introduced, and are usually involved with formation of other solid phases. None simplifying assumptions in the calculations were made.

Laminar natural convection heat transfer in inclined porous layers with multiple diathermal partitions is studied analytically and numerically. On the basis of the Darcy-Oberbeck-Boussinesq equations, the problem is solved analytically in the limit of a thin layer with constant flux boundary conditions. The relationship between overall heat transfer and the number of partitions N, their relative positions Nu and the angle of inclination φ of the system is determined The critical Darcy-Rayleigh number R c for the onset of convection in a bottom-heated horizontal system is predicted. The results are compared with limiting cases of the problem and are found to be in agreement. The influence of a thermal barrier which is sandwiched between two porous layers is also discussed. A numerical study of the same phenomenon, obtained by solving the complete system of governing equations, is conducted. A good agreement is found between the analytical predictions and the numerical simulation.

In nature water presents itself in solid, liquid and gaseous phases. Energy transfers during transformations among these phases have important consequences in weather and climate. The system of redistribution of water on the planet constitutes the hydrological cycle which is central to weather and climate research and operations. Water is also an important solvent in the oceans, soils and in cloud droplets. The presence of tiny particles in the air can influence the formation of cloud drops and thereby change the Earth's radiation balance between absorbed and emitted and/or reflected radiation. These and other effects lead us into the fascinating role of water in the environment. Of course, thermodynamics is an indispensable tool in unraveling this very challenging puzzle. Vapor pressure We start with a discussion of the equilibrium gas pressure in a chamber in diathermal contact with a reservoir at a fixed temperature, T 0 . The chamber is to have a volume that is adjustable, as shown in Figure 5.1. In the following let the chamber have no air present – only the gas from evaporation of the liquid. We are to choose a volume V such that there is some liquid present at the bottom of the chamber (we say here the bottom of the chamber, but otherwise we ignore gravity). There are gas molecules constantly striking the liquid from above and sticking. […]

This chapter introduces a set of idealized auxiliary thermodynamic systems with special properties that they possess by definition. These systems are the reversible work, heat, and matter sources and reservoirs. They are called “auxiliary systems” because they serve as components in composite systems whose main component is to be investigated. Their primary purpose is to assure constancy of one or the other intensive parameter such as temperature, pressure, or chemical potential in the main component. A very large reversible work source is called a “work reservoir.” If the work is pressure–volume work, the pressure of a volume reservoir is constant. Such a work reservoir acts as a “manostat.” Similarly in case of heat reservoir, temperature is constant. A heat reservoir coupled to another system through a diathermal wall acts as a “thermostat.” In a matter reservoir, the chemical potential of the species of which it consists is constant and it thus acts as a “chemostat.” In the interaction of a given thermodynamic system with a reversible heat, work, or matter source the total change in entropy is zero because the processes are reversible.

The calculations for the three diathermal calorimeter designs are given and their merits and dismerits are compared. The recommendations for the embodiment of the respective design versions are proposed.

A numerical study has been made of natural convection in an inclinded porous enclosure with an off-center diathermal partition. A temperature difference is imposed between the two isothermal end walls and the other two walls are assumed to be adiabatic. Numerical results are obtained for Rayleigh numbers (Ra) in the range of 10 to 500, the dimensionless partition location (\(\bar S\)) ranging from 0.125 to 0.875, the aspect ratios (A) of the enclosure ranging from 0.5 to 5, and the inclination angles (φ) of −60, −30, 0, 30, 60 degrees. It is found that the partition location has strong influence at lowRa and relatively weaker influence at highRa. The average Nusselt number reaches the minimum value when the partition is in the middle of the vertical enclosure, and the maximum Nusselt number occurs around φ = 30 degrees.

When adsorption calorimeters of the Beebe type are used with particulate adsorbents having low thermal conductivity, the assumption of thermal equilibrium in the calorimeter system is not valid. A differential equation is developed relating calorimeter wall temperature to the balance between cooling losses and heat transferred by the several internal conduction paths. Unique calorimeter parameters are obtained from cooling curve analysis for both calibration and adsorption processes. Techniques for resolving accurate heats of adsorption are discussed.

This numerical study documents the effect of internal flow obstructions on heat transfer through a 2-dim. porous layer heated from the side. Three types of flow obstructions have been considered. Horizontal diathermal partitions were found to decrease the heat transfer rate in cases where the overall heat transfer was dominated by convection. In the conduction-dominated regime, horizontal diathermal partitions were found to increase the heat transfer rate slightly. Horizontal adiabatic partitions, on the other hand, were found to increase the heat transfer rate when the dominating mechanism is convection. Finally, vertical diathermal partitions were shown to reduce the heat transfer rate by roughly 50% in the convection-dominated regime. Numerical heat transfer results are reported in the domain 0.1

PUBLISHED LITERATURE STRESSES THE PHYSIOCOCHEMICAL APPROACH TO CLAY SWELLING. IN THIS PAPER, EQUILIBRIUM THERMODYNAMICS IS EXPLORED AS ANOTHER APPROACH WORTHY OF CONSIDERATION, HOWEVER, THE MECHANISM OF SWELLING IS NOT INCLUDED. A MACROSCOPIC, HOMOGENEOUS MASS IS USED TO DESCRIBE THE COMPOSITION OF A CLAY-WATER SYSTEM WHICH IS FREE OF EXTERNAL FIELDS, INCLUDING GRAVITATIONAL FIELDS. AN EXAMPLE IS GIVEN OF A CLAY-WATER SYSTEM WHICH IS ENCLOSED BY MOVABLE, DIATHERMAL WALLS THAT ARE PERMEABLE ONLY TO LIQUID AND GAS PHASES. EQUATIONS ARE PRESENTED TO SHOW THE PHASES THAT A CLAY-WATER SYSTEM UNDERGOES IN REACHING A STATE OF THERMODYNAMIC EQUILIBRIUM. FOR A GIVEN QUASISTATIC PROCESS THE TEMPERATURE AND THE CLAY MASS ARE HELD CONSTANT WHILE CHANGES IN THE VOLUME OF THE CLAY-WATER SYSTEM AND CHANGES IN THE PRESSURE, BOTH FOR INTERNAL PRESSURE AND THE FINAL PRESSURE, OF THE WATER CONTENT HAD AFTER COMPRESSION AS NOTED. AS AN ALTERNATIVE METHOD OF PRESENTING THE VOLUME CHANGES, THE TRANSFER OF WATER FROM A SERIES OF RESERVOIRS IS DISCUSSED WITH APPROPRIATE EQUATIONS. IN ADDITION, THE GEOMETRY FACTOR, ALTHOUGH MENTIONED, IS NOT DISCUSSED BECAUSE OF ITS RELATIONSHIP TO THE MICROSCOPIC CONCEPTS OF THERMODYNAMICS. THE CLAY-WATER SYSTEMS WITH THE SAME TEMPERATURE, PRESSURE, AND WATER CONTENT ARE CONSIDERED WITH DIFFERENT BULK DENSITIES.