Chemical and Process Industries最新文献

{"title":"Evaporation Heat Transfer and Pressure Drop of HFC-134a Inside a Plate Heat Exchanger","authors":"B. Ouazia","doi":"10.1115/imece2001/pid-25613","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25613","url":null,"abstract":"\u0000 An experimental investigation was carried out to provide data on heat transfer coefficient and pressure drop for upward flow of refrigerant 134a in a typical plate heat exchanger. Upflow boiling of R-134a in one channel receives heat from the hot downflow of water in the two adjacent channels. Measurements were conducted on three sets of plates with chevron angles of 0°, 30°, and 60°, and the effects of mean vapor quality, mass flux, and heat flux on the evaporation heat transfer and pressure drop were explored. It was found that the channels with small chevron angle have higher heat transfer than channels with large chevron angle, for both subcooling and vapor quality inlet conditions. It was clear that the heat transfer coefficients were not sensitive to the heat flux but were dependent on the flow conditions (mass velocity and vapour quality). Based on the experimental data, empirical correlations for the evaporation heat transfer enhancement factor and the two-phase pressure drop multipliers were proposed.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87716757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Results on the Application of a High-Voltage Capacitance-Based Technology to Reduce Biofouling in Reverse Osmosis Systems","authors":"T. Fiadjoe, D. Chau, P. Phelan","doi":"10.1115/imece2001/pid-25618","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25618","url":null,"abstract":"\u0000 As the use of reverse osmosis (RO) machines becomes prevalent in our society, more attention is being paid to reducing their operational and maintenance costs. One method of improving efficiency is by adequate pretreatment of the feed water to the RO system. A proposed alternative to current chemical treatment methods is a novel high-voltage, capacitance-based system that utilizes electrostatic dispersion techniques. This alternative method of treatment was experimentally evaluated and was found to be effective in certain aspects of RO pretreatment. An experimental apparatus was designed based on two nominally identical household RO systems. The two systems were subject to identical, but variable, feed conditions. The technology proved effective in reducing the bacterial contamination levels in an RO system, although it did not completely eliminate the formation of biofilm.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91042092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modifications of a Two Stage Centrifugal Compressor for the Volute and Vaneless Diffuser Study","authors":"Hooman Rezaei, P. Haley, A. Engeda","doi":"10.1115/imece2001/pid-25604","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25604","url":null,"abstract":"\u0000 The objective of this work was to establish an advanced testing facility for studying the flow structure and loss mechanism in a single stage centrifugal compressor. A Trane’s CVHF 1280, two stage centrifugal compressor was modified to a single stage for laboratory environment. This modification included new fluid medium, driving motor, inlet and outlet designs. In this study, experiments were performed in order to evaluate the performance of the vaneless diffuser and volute. However, the modifications enable the flow structure investigation in all components of the compressor as well. In addition the testing facility would accommodate installation of the rest of the unit for investigation of the flow in the vaned diffuser and return channel of the two-stage compressor in the laboratory environment.\u0000 Experiments were performed in three speeds and eight mass flow rates per speed. Static and total pressures were measured at the inlet and outlet of the stage. Static pressure distributions were mapped on the vaneless diffuser and volute casings. These data evaluates the characteristics of these components after the modifications.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81829844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance Evaluation of Different Designs of Locomotive Intercoolers","authors":"V. Rajendran, A. Furman, Barry A. Record","doi":"10.1115/imece2001/pid-25607","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25607","url":null,"abstract":"\u0000 Heat exchangers of two different designs, used for the cooling of turbocharged air for locomotive diesel engines were experimentally studied to characterize the performance as well as to investigate the loss of effectiveness over time. Performance criteria including initial effectiveness, pressure drop and effectiveness degradation due to thermal shocks were characterized for a typical intercooler. Thermal and flow performance tests as well as severe shock tests were conducted in the laboratory at full-scale flow and geometric conditions to study the drop in effectiveness experienced in the field. The inlet Reynolds number for airside, based on the inlet flow conditions and pipe diameter is 2.13 × 105. The inlet Reynolds number for waterside, based on the inlet flow conditions and pipe diameter is 2 × 105. Mechanisms for the effectiveness drop due to thermal transients are discussed. Significant improvements in effectiveness degradation characteristics were achieved with a proposed new design while maintaining initial effectiveness. Overall, the new design was found to be significantly improved compared to the current design.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84231788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat and Mass Transfer Characteristics of a Finned-Tube Evaporator Under Frosting Conditions","authors":"Y. H. Kim, Y. J. Park, Yong Chan Kim, S. Shim, S. Oh, J. S. Lee","doi":"10.1115/imece2001/pid-25612","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25612","url":null,"abstract":"An experimental study was performed to investigate the heat and mass transfer characteristics of a finned-tube evaporator coil utilized in a domestic refrigerator under frosting conditions. Airside heat transfer coefficient was measured as a function of air temperature, humidity ratio, air velocity, and evaporating temperature. In addition, frost thickness was monitored and measured by visualization tests during frosting operation. Based on the experimental results, the degradation of heat transfer performance due to frost formation was explored as a function of operating parameters. The rate of frost formation on the evaporator increases at relatively high humidity, high airflow rate, low inlet air temperature and low refrigerant temperature. As the frost thickness increases, airflow rate gradually decreases, while the capacity increases at the early stage of frost formation and then significantly drops.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74270970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent Developments in High-Performance Refrigeration for the First Compact Cryogenic Freeze-Dryer","authors":"L. Reznikov, D. Sutherland","doi":"10.1115/imece2001/pid-25622","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25622","url":null,"abstract":"\u0000 Lyophilization, a process of drying of frozen materials with sublimation of solvents from frozen products, is one of the key processes in pharmaceutical industry for preparation of dry inert products. Traditionally, refrigeration for operations of freezing, primary and secondary drying of the moist products and for condensing of solvents has been supported by mechanical refrigeration.\u0000 Development of efficient, reliable cryogenic refrigeration with accurate temperature control and effective heat transfer processes have created premises for design of the first in the world cryogenic pump-free compact unit “Advantage LN2”.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82399702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forced Convective Heat Transfer From Helicoidal Pipes","authors":"A. Fakheri, Abdelrahman H. A. Alnaeim","doi":"10.1115/imece2001/pid-25610","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25610","url":null,"abstract":"\u0000 Forced convection heat transfer from helicoidal pipes is experimentally investigated over a wide range of operating conditions. Based on the experimental results, a characteristic length incorporating the tube diameter, the coil diameter, and the coil spacing, is proposed as the relevant scale for defining Nusselt and Reynolds numbers. Based on this characteristic length, Nusselt number for helicoidal pipes can be predicated from the correlations available for cylinders in the range of available experimental data. It is shown that the performance of the coils depends on the Reynolds number. At high Reynolds numbers, the heat transfer coefficient is essentially equal to that of the straight pipe and the coil pitch has little influence on the heat transfer rate. On the other hand, at low Reynolds numbers, the heat transfer coefficient is lower than that of a straight pipe and its value is a strong function of the coil spacing.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79435061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cryogenic Heat Engines for Powering Zero Emission Vehicles","authors":"C. Ordonez, M. Plummer, R. Reidy","doi":"10.1115/imece2001/pid-25620","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25620","url":null,"abstract":"\u0000 Progress on advancing the technology of using cold thermal reservoirs for mobile energy storage applications is reported. A heat engine such as a Stirling engine can operate using the cold thermal reservoir as a heat sink and the atmosphere as a heat source. A heat engine as developed by the authors that operates employing a sub-atmospheric temperature thermal reservoir such as liquid nitrogen as a heat sink has been called a “cryogenic heat engine.” With sufficient work produced per unit mass of liquid nitrogen, such a cryogenic heat engine may be suitable for powering short range, non-polluting automobiles.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73307841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Investigation of Distorted and Enhanced Inlet Flow Influence on the Performance of a Centrifugal Compressor Stage","authors":"Yunbae Kim, R. Aungier, A. Engeda, Gregory L. Direnzi","doi":"10.1115/imece2001/pid-25602","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25602","url":null,"abstract":"\u0000 The performance of a centrifugal compressor can be seriously affected by inlet flow distortions due to the unsatisfactory nature of the inlet configuration and the resulting inlet flow structure.\u0000 In the previous work, experimental tests were carried out for the comparison of a centrifugal compressor stage performance with two different inlet configurations: one of which was a straight pipe with constant cross-sectional area as an ideal model and the other is a 90-degree curved pipe with nozzle shape as an actual model. The comparative test results indicated significant compressor stage performance difference between the two different inlet configurations.\u0000 In addition, the numerical simulation part of the previous work clearly showed that the inlet flow distortion is caused by the pressure driven secondary flow developed in the curved section in the case of the bend inlet, resulting in locally concentrated incidence at the impeller inlet and thus the compressor stage performance degradation. An improved inlet model with the design method has been proposed based on the comparisons of the designated flow properties.\u0000 In the present work, further numerical simulations on the compressor stage including the impeller and the diffuser with three different inlets are carried out to investigate the performance behavior of the compressor exposed to different inlet configurations. The three different inlet systems include the original bend inlet as well as the proposed inlet model based on the developed design method.\u0000 Since the flow from the bend inlet is not axisymmetric due to the circumferential and radial distortion on the cross-section, the impeller and the diffuser are modeled with fully 360-degree passages, which accommodates the inlet flow distortion and the impeller-diffuser interaction influence on the entire flow passage of the compressor. The stage performance with the different inlet systems are evaluated and compared with the previous experimental result. The diffuser performance and the flow properties in the vaneless region are compared among those inlet models. The proposed inlet system indicated the benefit of performance improvement over the original inlet system.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"97 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75921501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Measurement of the Natural Convection Heat Transfer for Horizontal Helicoidal Pipes","authors":"Getnet S. Kidane, A. Fakheri","doi":"10.1115/imece2001/pid-25609","DOIUrl":"https://doi.org/10.1115/imece2001/pid-25609","url":null,"abstract":"\u0000 The natural convection heat transfer coefficient for the helicoidal coils are experimentally measured and compared with those for horizontal cylinders. It is found that when the coil pitch to pipe diameter ratio is less than around 1.2, the heat transfer coefficient of the coils approaches that of a horizontal cylinder having a diameter equal to the coil diameter. For the P/d ratio greater than 1.4, the heat transfer coefficient approaches that for horizontal cylinder of diameter d. A modified characteristic, length which incorporates the tube diameter, the coil diameter, and the coil spacing, is used to define Nusselt and Rayleigh numbers. Using the proposed characteristic length, it is shown that the Nusselt number for horizontal helicoidal pipes can be determined using the available Nusselt and Rayleigh number correlation for straight horizontal cylinders in the range of the experimental and available data, Ra ≤ 105, within a maximum deviation of 15.4%.","PeriodicalId":9805,"journal":{"name":"Chemical and Process Industries","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77696398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}