H. R. Jacobs

Bio: H. R. Jacobs is an academic researcher from Pennsylvania State University. The author has contributed to research in topics: Heat exchanger & Heat transfer. The author has an hindex of 4, co-authored 5 publications receiving 60 citations.

Direct-Contact Heat Transfer for Process Technologies

Abstract: Direct-contact heat transfer processes between fluid streams are reviewed for situations that may be found in process technologies. While not all of the past work could be referenced in the space available, many current and review articles are cited that provide sources of detailed information. Included in this review are topics that relate to direct contact evaporation, condensation, and boiling as well as simple sensible heat transfer between the fluid streams.

A Heuristic Evaluation of the Governing Mode of Heat Transfer in a Liquid–Liquid Spray Column

Abstract: A steady-state one-dimensional multiphase flow model is developed to describe the characteristics of a spray column type direct-contact liquid-liquid heat exchanger. Several models are assumed to describe the interphase heat exchange between water as the continuous phase and organic liquids as the dispersed phase. For small-diameter droplets, it is shown that existing experimental data are best described by a model that assumes the heat transfer is controlled by conduction within the drops

Stability of a Direct-Contact Spray Column Heat Exchanger

Abstract: The governing equations for the transient multiphase flow in a liquid-liquid spray column are developed. Using the model, numerical calculations are presented that represent typical fluctuations observed in the operation of the direct contact tower of the geothermal power plant at East Mesa. The response time is determined for the column and conditions leading to local flooding are determined

Condensation on Coolant Jets and Sheets Including the Effects of Noncondensible Gases

Abstract: The study of condensation of a pure vapor or a mixture of a vapor and a non-condensible gas on a laminar cylindrical jet or a falling sheet can provide the necessary information for designing cascade, curtain, or jet-type direct contact condensers. Prior to the present work the only theoretical solutions were based on the solution of the Graetz problem and were thus restricted to problems where the Jakob number is zero. Using an integral formulation of the governing equations, an extension is made which provides results for practical values of both the Jakob and Graetz numbers. For the case where noncondensibles are present, detailed results are presented for the steam-air system.

An Experimental Study of Direct Condensation on a Fragmenting Circular Jet

Abstract: Direct-contact heat exchangers have received increasing attention in recent years because of their simplicity of construction, compactness, and high heat transfer rate. The present experiments were undertaken to provide technical data for the design of jet-type direct-contact heat exchangers in the laminar flow range. Flow instability and the transition from a circular jet to droplets were observed and discussed. A comparison between the measured heat transfer rate and the heat transfer rate predicted by Jacobs and Nadig's (1987) analytical models for a laminar circular jet is also given in the present investigation. It is found that the measured heat transfer rate is slightly slower than that predicted by Jacobs and Nadig's analytical model for pure vapor; however, the experimental data agree well with the analytical solution the effects of the air content in steam are taken into account.

Gas‐Liquid Direct‐Contact Evaporation: A Review

Abstract: Gas-liquid direct-contact evaporators are characterized by the bubbling of a superheated gas through the solution to be concentrated. In other words, they are nonisothermal bubble columns. Despite their simplicity of construction, these units exhibit rather complex hydrodynamics and, similar to what occurs to isothermal bubble columns, the design of such units still poses a problem. The present paper reviews the literature regarding this kind of equipment, addressing both experimental studies and modeling efforts. The covered issues include classic and potential applications, bubbling regimes, gas holdup and bubble size distributions, as well as mathematical models proposed for simulating the unit. Additionally, pertinent literature on isothermal bubble columns is also discussed. Recommendations are made for future research.