Abstract: The influences of headspace, rotational speed of the can, and product viscosity on the rates of heat transfer during flame-sterilization of carboxy-methyl-cellulose (CMC) model solutions, were studied. It was observed that more than 90% of the heat transfer resistance was external, and so the headspace volume and product viscosity had almost no effect on the rates of heat transfer, whilst the can rotational speed was the important parameter that needed to be controlled. An empirical correlation between the Nusselt, Reynolds and Prandtl dimensionless numbers for the external and internal conditions was obtained, in order to describe the heat transfer as a function of the hot air and product thermophysical properties, the can r.p.m. and the diameter. The results will be useful for improving flame-sterilizer utilization.

Abstract: SYNOPSIS The results of a test programme of a completely fluorinated organic fluid solar engine at fluid temperatures around 250°C are Engine design characteristics. as deduced using the particular fluid properties are briefly described problems encountered in the preliminary test phase and relating to fluid losses, heat exchangers reduced performance and minor mechanical disturbances are illustrated together with the actions undertaken to improve the original engine behaviour. Detailed engine overall and components performance, as derived from a series of tests, carried out with a fuel fired heat source (simulating the actual solar heating loop) are presented. Engine efficiency, with reference to the net power output at the high speed shaft proved to be around 21%, at 250°C turbine inlet temperature which can be compared with 22.6% design value at the same temperature and with 23.6% original goal at 280°C top cycle temperature. The analysis of the heat transfer coefficients within the various heat exchan...

Abstract: Packed bed heat exchangers for thermal energy storage systems are investigated by means of two phase heat transfer models. The paper is mainly aimed at deriving analytical solutions to the thermal balance equations relevant to different kinds of packed beds, taking into account the roles played by heat capacity and conduction effects. The results are shortly discussed and some graphs are shown for situations typical of various operational modes.

Abstract: A temperature control method for a reversing type heat exchanger group wherein an outlet temperature of reheating gas of an arbitrarily selected reversing type heat exchanger which serves as a reference in the reversing heat exchanger group is rendered equal in value to a reference control temperature set beforehand in such a manner so as to satisfy the sweeping temperature difference. The outlet temperatures of the reheating gas in the other reversing type heat exchangers of the reversing type heat exchanger group are rendered equal in value to the outlet temperature of the reheating gas in the reversing type heat exchanger serving as the reference. Thus, the temperature of the cold end of all of the reversing type heat exchangers of the reversing type heat exchanger group are caused to be balanced equally whereby ice and dry ice deposited on the feed water channels can be effectively removed by a sweeping action.

Abstract: PURPOSE:To improve the efficiency by the addition of ventilating and humidifying capacity by a method wherein combustion exhaust gas mixed with the air in an intake chamber is made to pass through a total heat exchanger and discharged from the chamber, whereas the air outside the chamber is taken in through the total heat exchanger in order to allow both to exchange heat and humidity. CONSTITUTION:Combustion gas in a combustion part 3 is discharged into a mixing section 7 as shown by a black arrow and mixed with the air taken in from an inside A as shown by a white arrow and then discharged from a discharge port through a total heat exchanger 13. On the other hand, the air in an outside B is taken in by a blower 11 and sent into the inside A through the total heat exchanger 13. In the meantime, the air outside and the mixed air are allowed to exchage heat for humidity by means of the total heat exchanger 13, so that the outdoor air is heated and humidified. Thus a hot air type space supplying heater with ventilating and humidifying capability, and excellent heat exchanger effectiveness can be obtained.

Abstract: Post-critical heat flux heat transfer data for water in downflow have been obtained for the following conditions: mass velocity, 48.8 to 147 kg/sXm/sup 2/; wall temperature, 538 to 760/sup 0/C; pressure, 1.3 to 2.6 bars; quality, 4.1 to +5.8%; tube diameter, 1.25 cm; and tube length, 66 cm. At low mass velocity, a frozen equilibrium model predicts the data well. At high mass velocity, droplet-vapor heat transfer is good enough so that a homogeneous equilibrium model predicts the data. Under no circumstances is droplet-wall heat transfer significant. When the vapor is in laminar flow, the heat transfer is particularly poor and the radiant heat transfer becomes a significant fraction of the total.

Abstract: A paucity of heat transfer rate data for boiling two-phase flow through bends was noted after an extensive literature survey, The present work was undertaken to redress this shortcoming. A boiling water loop, capable of being operated at pressures up to 1300 kpa, was used. The lest section was in the form of a U-tube with two straight horizontal sections connected by a 180° return bend. Using this loop, pressure drop and heat transfer data were gathered over a wide range of mass and heat fluxes. steam qualities and system pressures. The data obtained were used to investigate the variation in heal transfer coefficients around the radial positions of the bend. Correlations for heat transfer coefficients for four different radial positions (top. bollom, inside and outside of the bend) have been presented for the first time. A possible explanation for the observed variations in heat transfer coefficients has also been suggested.

Abstract: Heat transfer simulation method in boiler furnace was developed to obtain temperature distribution and heat absorbing rate distribution in the furnace. The results were compared with experimental data from a small boiler for heavy oil. The method analyzes simultaneously the three dimensional viscous flow by vector potential method, combustive heat generating rate by a flame model with Wiebe's function, three dimensional radiative heat transfer by Monte Carlo method, and convective heat transfer and enthalpy transport due to the flow by finite difference method. Following results were obtained by this simulation.(1) The effects on in-furnace heat transfer of the flow pattern are rather small compared with the effects of the heat generating rate distribution.(2) Heat generating rate in boiler furnaces were made possible to be estimated by determining the Wiebe's function's parameters in the flame model by comparing the analytical results with the experimental one's.(3) Relationship among the heat generating rate and the fuel flow rate and the air fuel ratio was investigated, and by using this, analytical results of temperature and heat absorbing rate distributions were obtained with practically sufficient degree of accuracies compared with the experimental results.

Abstract: Analytic expressions are derived for the temperatures of a heat-exchanger solid and coolant.

Abstract: The design of the basic rock bed-earth heat exchanger is described in some detail. A finite difference analysis of the heat exchanger is presented and points out the role of the rocks and the earth in the thermal performance. It is seen that the rocks create a time lag or “flywheel” effect on the short term daily temperature variations while the earth environment controls the monthly variations in temperature level. The heat exchanger is shown to be a very good air tempering system which can produce an earth-like environment above ground.

Abstract: A simple analysis is presented for modeling step heat exchangers for the dilution refrigerator. The model incorporates the effects of external heat leaks and the Kapitza boundary resistance. Theoretical temperatures of the heat exchangers and of the mixing chamber are in acceptable agreement with experimental results. Predictions suggest that temperatures of 6 mK can be achieved using three‐step heat exchangers and a He3 circulation rate of 90 μmoles/s.

Abstract: The possibility of improving the match between an energy source and an energy sink in an energy exchange system has been investigated to maximize both energy conservation and economic benefit. Trade-off curves between the total dissipation of available energy (exergy) and the total area of heat exchangers in the system have been obtained under three situations. In the first problem it is assumed that any heat source, of whatever quality and quantity, can be used for heat exchange. In the second problem available heat sources are specified and then the network of heat exchangers is synthesized. In the last problem, sizing of each heat exchanger is considered under the specified heat sources and heat exchanger network. Comparison of these trade-off curves suggests that an appropriate heat source or sources should be chosen by solving the heat source selection problem before the synthesis or design of a heat exchange system is carried out.