Boiler Temperature Research Articles

Experiments on vapour jet refrigeration system suitable for solar energy applications

Experiments are carried out on a R11 vapour jet refrigeration system (VJRS) to study the influence of ejector configuration and operating conditions on the performance. Eight ejector configurations, formed out of five nozzles and seven diffusers are investigated. The influence of boiler temperature, which represents the solar energy collection temperature, and that of evaporating temperature, which denotes the cooling load temperature, are studied. Overall COPs in the range of 0.08-0.33 and evaporating temperatures in the range of −3–18°C are obtained for boiler temperatures from 75 to 85°C. Ejector configuration has significant influence in deciding the operating range.

Theory for Aerosol Generation in Laminar Flow Condensers

Generation of aerosols in laminar flow condensers is investigated theoretically. A model is developed for simultaneous heat and vapor mass transfer, aerosol nucleation, condensation, coagulation, thermophoresis, and diffusion representing the aerosol size distribution by a lognormal function throughout the process. The importance of the above physical phenomena and the effect of process parameters (reheater and boiler temperature, seed nuclei concentration) on product aerosol characteristics (average particle size and concentration, polydispersity, and yield) and condenser length are investigated. The effects of the classical Becker-Doering and the Lothe-Pound theories for homogeneous nucleation on product aerosol characteristics are examined. Nucleation and condensation are the controlling aerosol phenomena in production of aluminum sec butoxide and dibutylphthalate aerosols in laminar flow condensers. This theory is in good agreement with theoretical and experimental results in literature.

A simplified procedure for the estimation of Rankine power cycle efficiency

A simplified procedure for estimating the Rankine power cycle efficiency η R is presented. This procedure does not need any detailed thermodynamic data but requires only the liquid specific heat and the latent heat of vaporization at boiler temperature. This procedure is tested for its application to eight potential Rankine power cycle working fluids for which exact η R values have been reported based on detailed thermodynamic data. A fairly wide range of condensing and boiling temperatures is covered. The results indicate that the present procedure can predict η R values within ±1%.

Factors affecting aerosol production from a modified sinclair-la mer aerosol generator

A systematic study was made of the aerosol output from a Sinclair-LaMer aerosol generator incorporating a modified nuclei source, a polydisperse aqueous aerosol. This system makes monodisperse aerosols with biologically active nuclei and can be used in studies of lung physiology. Using radiolabelled nuclei and cascade impaction we found that aerosols were generated in keeping with the same concepts that apply to the classic Sinclair-LaMer system. That is, a balance exists between the amount of oil vapor and the number of nuclei in the system, and that this balance influences the size and distribution of the aerosol particles. The influence of boiler temperature ( T- B), reheater temperature ( T- R), gas flow ( V), and solute concentration ( SC) on aerosol particle size, distribution, and concentration was studied. We found that when monodisperse, T- B, T- R, V, and SC did not significantly affect distribution but did affect particle size. Aerosols produced under conditions of oil vapor or nuclei excess were also characterized. When nuclei were in overabundance (low T- B, T- R; high V, SC) the aerosol was polydisperse but concentration was unaffected. With excess oil vapor (high T- B, T- R; low V, SC) the polydisperse distribution was associated with a marked increase in concentration due to autocoagulation.

Ejector-compression systems for cooling: Utilising low grade waste heat

The ejector-compression system is an attractive means of cooling, using low grade thermal energy in the temperature range of 70–90°C as heat input to the cycle. This energy is available from flat plate solar collectors, waste steam, exhaust from automobiles and flue gases etc. The effects on mass flow ratio of motive vapour to evaporator vapour, condenser heat capacity and coefficient of performance, have been studied as a function of boiler temperature by varying the evaporator and condenser temperatures for promising refrigerants such as R-11 and R-113.

Aerosol studies by light scattering. VII. Preparation and particle-size distribution of linolenic acid aerosols

Linolenic acid aerosols of narrow size distribution are generated by condensation of vapor upon NaCl and AgCl nuclei in a helium gas stream. The particle-size distribution is determined by analysis of the angular distribution of the polarization ratio of the scattered light. In addition, the particle concentration is obtained from the absolute value of the Rayleigh ratio. These aerosol particles can be solidified for electron microscopic observation with OsO 4, and this has permitted a comparison of the light-scattering results with electron microscopy. Also, the determination of particle concentration from measurement of the Rayleigh ratio has been compared with direct collection by thermal precipitation and filtration and subsequent acidimetric titration. The performance of the aerosol generator has been studied with respect to operating conditions such as flow rate, boiler temperature, nuclei furnace temperature, and nuclei concentration.

Measurement of the superheat temperature of the TP-100 boiler

Measurement of the superheat temperature of the TP-100 boiler

Aerosol studies by light scattering: VI. Preparation and growth of sulfuric acid aerosols

Sulfuric acid aerosols consisting of droplets of narrow size distribution in the tenth micron size range have been prepared by an evaporation-condensation technique, and the particle size distribution has been determined by light scattering. The particle size increased with increasing boiler temperature and decreased sharply with flow rate. The use of foreign nuclei such as NaCl was of no advantage in the preparation. The spread of the distribution as measured by the coefficient of variance ranged from about 0.10 to 0.30. These aerosols could be grown by passing over dilute solutions of sulfuric acid. The sulfuric acid droplets absorbed water until their vapor pressure reached that of the master solution. The extent of growth depended upon contact time varying from about 3% increase in average radius for 10 −1 sec. to equilibration for about 100 sec. The coefficient of variance remained approximately constant upon growth, indicating that the rate of growth was proportional to particle volume.

Aerosol studies by light scattering. II. Preparation of octanoic acid aerosols of narrow and reproducible size distributions

Octanoic acid aerosols, in the submicron range and of narrow size distribution, were produced with excellent reproducibility when nucleated with silver chloride evaporated in a combustion furnace. The particle size distribution could be determined uniquely and with high precision from light scattering data using the polarization ratio method described in the preceding paper. The effects of the flow rate of the carrier gas, the nuclei concentration, the temperature of the furnace used for making the AgCl nuclei, and the temperature of octanoic acid in the boiler upon the size distribution of the aerosol were systematically investigated. With increasing flow rate at constant boiler temperature both the particle size and the polydispersity decrease. At a constant flow rate the particle size becomes larger with increasing boiler temperature while the polydispersity remains practically constant. Particle size also increases with decreasing furnace temperature and dilution of nuclei.

The Dynamic Characteristics of Steam Temperature of Boiler

The Dynamic Characteristics of Steam Temperature of Boiler

Light scattering of coated aerosols: II. Scattering by linolenic acid aerosols

Linolenic acid aerosols exhibiting higher order Tyndall spectra and comparable in monodispersity to monodisperse sulfur sols have been prepared reproducibly using silver chloride nuclei. Particle size distributions can be obtained precisely by analysis of the light-scattering data and when appropriate precautions in sampling are observed, excellent agreement with electron microscope counts is found. Samples are fixed for electron microscopy by treatment with OsO 4. The influence of boiler temperature, nuclei concentration, and dilution of the aerosol upon the light scattering and particle size distribution has been considered.

Characteristic for Booster Pump of Multi Nozzle Type (1)

The optimum number of nozzles of booster vacuum pump having ten and twenty nozzles of convergent-divergent type on the upper and lower circumferences of conical chimney respectively was determined varying the number of nozzles and boiler temperature and measuring the pumping speed and back pressure performance.

油によるブースターの特性の変化

Influences of the various pumping fluids on the operating performance of 8″ ejector booster type vacuum pump are examined.The fluids used are diethylphthalate, dibutylphthalate and hydrocarbon oil (mean molecular weight=250). Another combined factors, i. e. diameter of throttle, heat input, foreside pressure are also changed together.The authors have gotten some effective informations with these three pumping fluids about the relations between evacuating speed and heat input, boiler pressure and heat input, boiler temperature and heat input respectively.

Correction - "Removal of Silica from Solution at Boiler Temperature"

Correction - "Removal of Silica from Solution at Boiler Temperature"

The Formation and Thermal Effects of Calcium Sulphate Boiler Scale

Abstract A fundamental study of the manner in which calcium sulphate scale forms upon an evaporative surface, a redetermination of the solubility values for calcium sulphate in the boiler temperature range, and measurements of the rate of formation and heat conductivity of calcium sulphate scales produced in an experimental boiler, are described in abstract in this paper. Evidence is presented to show that the initial deposition of calcium sulphate scale takes place as the result of the evolution of bubbles, either of dissolved gas or of steam, from an evaporative surface, and that the continued growth of scale is dependent upon the fact that the solubility of calcium sulphate decreases with temperature increase. The work of the authors thus presents a new explanation of the mechanism of initial scale formation, supports Hall’s theory of the growth of scale, negates the colloidal theory of scale formation, and offers a fundamental basis for the study of scale-prevention methods. Photomicrographs of the early stages of deposition and growth of calcium sulphate scale are shown, as well as photomicrographs of scales produced under varying conditions. From the results of their own work and from that of other investigators, the authors present a discussion of the present knowledge concerning calcium sulphate scale. While the effect of scale upon heat utilization in modern boilers is believed to be very slight, calculations based on the heat conductivity of anhydrite scale indicate the importance of preventing overheating of tubes due to the insulating effect of scale deposits within them.