Aircraft equipment. Environmental and operating conditions for airborne equipment. Humidity, temperature and pressure tests

1996 ◽  
Keyword(s):  
Operating Conditions ◽  
Pressure Tests ◽  
Temperature And Pressure

scholarly journals Sub- and Supercritical Extraction of Slovenian Hops (Humulus lupulus L.) Aurora Variety Using Different Solvents

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1137
Author(s):  
Katja Bizaj ◽  
Mojca Škerget ◽  
Iztok Jože Košir ◽  
Željko Knez
Keyword(s):  
Sulfur Hexafluoride ◽  
Total Yield ◽  
Extraction Yield ◽  
Operating Conditions ◽  
Influence Of Process Parameters ◽  
Humulus Lupulus L ◽  
Bitter Acids ◽  
Temperature And Pressure ◽  
Carbon Dioxide Co2 ◽  
The Mathematical Model

This work investigates the efficiency of supercritical fluid extraction of hops with a variety of solvents including carbon dioxide (CO2), propane, sulfur hexafluoride (SF6), and dimethyl ether (DME) at various densities (low-density and high-density). Operating parameters were 50 bar, 100 bar and 150 bar and 20 °C, 40 °C, 60 °C and 80 °C for all solvents, respectively. The influence of process parameters on the total yield of extraction and content of bitter acids in the extracts has been investigated. The mathematical model based on Fick’s second law well described the experimental extraction results. Furthermore, HPLC analysis has been used to determine α- and β-acids in extracts. The yield of bitter compounds in hop extracts was largely influenced by the type of solvent, the temperature and pressure applied during extraction. The results show that CO2 and propane were roughly equivalent to DME in solvating power, while SF6 was a poor solvent at the same conditions. The highest yield as well as the highest concentration of bitter acids in extracts were obtained by using DME, where the optimal operating conditions were 40 °C and 100 bar for the extraction of α-acids (max. concentration 9.6%), 60 °C and 50 bar for the extraction of β-acids (4.5%) and 60 °C and 150 bar for the maximum extraction yield (25.6%).

The Influences of Reaction Conditions on Phenanthrene Hydrogenation over NiW/Al2O3 Catalyst

2012 ◽  
Vol 512-515 ◽  
pp. 2200-2206
Author(s):  
Kun Wang ◽  
Jun Guan ◽  
De Min He ◽  
Qiu Min Zhang
Keyword(s):  
Positive Impact ◽  
Volume Ratio ◽  
Operating Conditions ◽  
Reaction Conditions ◽  
Remarkable Effect ◽  
Ms Analysis ◽  
Temperature And Pressure ◽  
Cracking Products

Hydrogenation of phenanthrene (PHE HYD) was investigated over a commercial NiW/Al2O3catalyst under practical reaction conditions. GC-MS analysis was utilized to identify the numerous products formed during PHE HYD. The products included dihydrophenanthrene (DHP), 1,2,3,4-tetrahydrophenanthrene (THP), sym-octahydrophenanthrene (1,8-OHP), asym-octahydrophenanthrene (1,10-OHP) and perhydrophenanthrene (PHP), but the cracking products were not found under the reaction conditions. The effects of operating conditions such as temperature, pressure and H2/liquor on PHE HYD were tested in detail. It is found that temperature and pressure had remarkable effect on PHE HYD, but volume ratio of H2/liquor had little effect on PHE HYD at the observation range. The addition of decalin had a positive impact on PHE HYD; it could increase the conversion of PHE and the selectivity to PHP.

Heat transfer characteristic modelling and the effect of operating conditions on re-cooled cycle for a scramjet

2011 ◽  
Vol 115 (1164) ◽  
pp. 83-90 ◽  
Author(s):  
W. Bao ◽  
J. Qin ◽  
W. X. Zhou
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Transfer Characteristic ◽  
Cooling Capacity ◽  
Sensitivity Study ◽  
Performance Model ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Fuel Flow ◽  
Temperature And Pressure

Abstract A re-cooled cycle has been proposed for a regeneratively cooled scramjet to reduce the hydrogen fuel flow for cooling. Upon the completion of the first cooling, fuel can be used for secondary cooling by transferring the enthalpy from fuel to work. Fuel heat sink (cooling capacity) is thus repeatedly used and fuel heat sink is indirectly increased. Instead of carrying excess fuel for cooling or seeking for any new coolant, the cooling fuel flow is reduced, and fuel onboard is adequate to satisfy the cooling requirement for the whole hypersonic vehicle. A performance model considering flow and heat transfer is build. A model sensitivity study of inlet temperature and pressure reveals that, for given exterior heating condition and cooling panel size, fuel heat sink can be obviously increased at moderate inlet temperature and pressure. Simultaneously the low-temperature heat transfer deterioration and Mach number constrains can also be avoided.

A thermodynamic performance analysis on influence parameters of COG-CCHP based on exergy

2018 ◽  
Vol 15 (6) ◽  
pp. 771-785
Author(s):  
Hongbin Zhao ◽  
Yu Cao ◽  
Chang Liu ◽  
Xiang Qi
Keyword(s):  
Energy Consumption ◽  
Energy Loss ◽  
Volume Fraction ◽  
Coke Oven ◽  
Integrated System ◽  
Operating Conditions ◽  
Weak Links ◽  
Coke Oven Gas ◽  
Content Type ◽  
Temperature And Pressure

PurposeThe purpose of this paper is to investigate the performance of coke oven gas (COG)-combined cooling, heating and power (CCHP) system and to mainly focus on studying the influence of the environmental conditions, operating conditions and gas conditions on the performance of the system and on quantifying the distribution of useful energy loss and the saving potential of the integrated system changing with different parameters.Design/methodology/approachThe working process of COG-CCHP was simulated through the establishment of system flow and thermal analysis mathematical model. Using exergy analysis method, the COG-CCHP system’s energy consumption status and the performance changing rules were analyzed.FindingsThe results showed that the combustion chamber has the largest exergy loss among the thermal equipments. Reducing the environmental temperature and pressure can improve the entire system’s reasonable degree of energy. Higher temperature and pressure improved the system’s perfection degree of energy use. Relatively high level of hydrogen and low content of water in COG and an optimal range of CH4volume fraction between 35 per cent and 46 per cent are required to ensure high exergy efficiency of this integration system.Originality/valueThis paper proposed a CCHP system with the utilization of coke oven gas (COG) and quantified the distribution of useful energy loss and the saving potential of the integrated system under different environmental, operating and gas conditions. The weak links of energy consumption within the system were analyzed, and the characteristics of COG in this way of using were illustrated. This study can provide certain guiding basis for further research and development of the CCHP system performance.

Empirical Model of Operating Temperature and Pressure Effect towards Pure and Binary O2/ N2 Gas Permeability in Polysulfone Membrane

2018 ◽  
Vol 777 ◽  
pp. 238-244
Author(s):  
Serene Sow Mun Lock ◽  
Kok Keong Lau ◽  
Irene Sow Mei Lock ◽  
Azmi Mohd Shariff ◽  
Yin Fong Yeong ◽  
...  
Keyword(s):  
Empirical Model ◽  
Membrane Separation ◽  
Gas Permeability ◽  
Economic Assessment ◽  
Operating Conditions ◽  
Effect Of Temperature ◽  
Polysulfone Membrane ◽  
Wide Range ◽  
Temperature And Pressure ◽  
Membrane Permeance

Oxygen (O2) enriched air combustion via adaption of polymeric membranes has been proposed to be a feasible alternative to increase combustion proficiency while minimizing the emission of greenhouse gases into the atmosphere. Nonetheless, majority of techno-economic assessment on the O2 enriched combustion evolving membrane separation process are confined to assumption of constant membrane permeance. In reality, it is well known that membrane permeance is highly dependent upon the temperature and pressure to which it is operated. Therefore, in this work, an empirical model, which includes the effect of temperature and pressure to permeance, has been evaluated based on own experimental work using polysulfone membrane. The empirical model has been further validated with published experimental results. It is found that the model is able to provide an excellent characterization of the membrane permeance across a wide range of operating conditions for both pure and binary gas with determination coefficient of minimally 0.99.

MmNi5 and MmNi4.85Fe0.15 as Hydrogen Storage Medium

2012 ◽  
Author(s):  
Anwar Johari ◽  
Rosli Mohd. Yunus ◽  
Mohd. Suffian Noordin ◽  
Mohd. Nazlee Faisal Md. Ghazali ◽  
Tuan Amran Tuan Abdullah
Keyword(s):  
Hydrogen Storage ◽  
Plateau Pressure ◽  
Absorption Capacity ◽  
Hydrogen Gas ◽  
Operating Conditions ◽  
Activation Process ◽  
Hydride Hydrogen ◽  
Temperature And Pressure ◽  
Pressure Hydrogen ◽  
Hydrogen Storage Medium

Ciri–ciri MmNi5 dan MmNi4.85Fe0.15 sebagai medium gas hidrogen telah dilakukan di dalam penyelidikan ini. Keupayaan penyerapan logam tersebut adalah dipengaruhi oleh faktor suhu dan dan tekanan. Julat suhu yang dipilih adalah di antara 298K dan 323K manakala tekanan diubah–ubah dari 2 hingga 30 bar. Dalam penyelidikan ini didapati bahawa jumlah gas hidrogen yang diserap oleh MmNi5 adalah berkadar songsang dengan suhu. Jumlah penyerapan maksimum NmNi5 telah dicapai pada suhu 298K dan pada tekanan plateau 10 m bar. Nilai penyerapan hidrogen pada suhu dan tekanan tersebut adalah 1.20 peratus berat. Bagi penyerapan MmNi5 pada 313K dan 323K, keputusan menunjukkan nilai 0.9 dan 0.8 peratus berat. Masing–masing menunjukkan tekanan plateau didapati pada 20 dan 24 bar. Penyelidikan ke atas MmNi4.85 menunjukkan keputusan yang tidak menepati dengan teori. Hasil daripada rujukan dan penyelidikan yang menyeluruh, didapati bahawa proses pengaktifan sampel yang dilakukan adalah tidak mencukupi untuk mengaktifkan MmNi4.85Fe0.15. Kata kunci: Logam hidrid; penyimpanan gas hidrogen; proses pengaktifan; tekanan plateau; jumlah penyerapan hidrogen The characteristics of MmNi5 and MmNi4.85Fe0.15 in storing hydrogen gas were examined in this study. The absorption capacity of the metal was monitored under the influence of temperature and pressure. Due to the limitation on its operating conditions, the range of the temperature chosen was from 298K to 323K while pressure was varied from 2 to 30 bar. Study conducted on MmNi5, showed that the amount of hydrogen absorbed was inversely proportional to the operating temperature. In the study of MnNi5 the maximum absorption was achieved at 298K and exhibited the plateau pressure of 10 bar. The hydrogen content was expressed as weight and the value was calculated to be at 1.20 wt%. As for MmNi5 at 313K abd 323K, the results are pointed at 0.9 wt% and 0.8 wt% whilst the plateau was encountedered at 20 and 24 bar, respectively. Study conducted on MmNi4.85Fe0.15 showed inconsistent findings with theory. After thorough examination, it was realized that the misbehavior of the sample was due to the insufficient agrresiveness activations method employed. Key words: Metal hydride; hydrogen storage; activation process; plateau pressure; hydrogen absorbed content

Applicability of Pump Models for Varying Operational Conditions

2003 ◽  
Author(s):  
Heikki O. J. Kauranne ◽  
Jyrki T. Kajaste ◽  
Asko U. Ellman ◽  
Matti T. Pietola
Keyword(s):  
Rotational Speed ◽  
Operating Conditions ◽  
Fluid Temperature ◽  
Limited Information ◽  
Operational Conditions ◽  
Axial Piston Pumps ◽  
Pump Construction ◽  
Temperature And Pressure ◽  
Axial Piston ◽  
Type Pressure

It is commonly known that the characteristics of a fluid power pump depend on pump type, pressure, rotational speed and displacement. But in addition to these, also all the other parameters or factors associated with the operating conditions may have a significant effect on the characteristics. The most important of these are the pump construction and size, operating point temperature and the characteristics of the oil, which also depend on temperature and pressure. The aim of this study is to show the effects that the varying operational conditions have on the characteristics of a axial piston pump, to compare the measured characteristics with other published characteristics of axial piston pumps and to study the capability of pump models to represent these characteristics. The results include information of the effects of fluid temperature, type of fluid and the setting value of the displacement on the pump characteristics along with the effects of pressure and rotational speed. The sensitivity of the pump to each of the parameters is discussed. The effect of limited information of pump characteristics on the reliability of simulation results is studied using the Schlo¨sser models.

Scoping Analyses of Parameterized Cool-Down Transients Associated With Reactor Shutdown

2007 ◽  
Author(s):  
T. L. Dickson ◽  
M. T. EricksonKirk
Keyword(s):  
Nuclear Reactor ◽  
Structural Integrity ◽  
Operating Temperature ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Pressure Vessels ◽  
Operating Conditions ◽  
Temperature And Pressure ◽  
Reactor Operating ◽  
Technical Basis

The current regulations, as set forth by the United States Nuclear Regulatory Commission (NRC), to insure that light-water nuclear reactor pressure vessels (RPVs) maintain their structural integrity when subjected to planned startup (heat-up) and shutdown (cool-down) transients are specified in Appendix G to 10 CFR Part 50, which incorporates by reference Appendix G to Section XI of the ASME Code. The technical basis for these regulations contains many aspects that are now broadly recognized by the technical community as being unnecessarily conservative. During the past decade, the NRC conducted the interdisciplinary Pressurized Thermal Shock (PTS) Re-evaluation Project that established a technical basis to support a risk-informed revision to current PTS regulations (10CFR Part 50.61). Once the results of the PTS reevaluation are incorporated into a revision of the 10 CFR 50 guidance on PTS, it is anticipated that the regulatory requirements for the fracture toughness of the RPV required to withstand a PTS event (accidental loading) will in some cases be less restrictive than the current requirements of Appendix G to 10 CFR Part 50, which apply to normal operating conditions. This logical inconsistency occurs because the new PTS guidelines will be based on realistic models and inputs whereas existing Appendix G requirements contain known and substantial conservatisms. Consequently, a goal of current NRC research is to derive a technical basis for a risk-informed revision to the current requirements of Appendix G to 10 CFR Part 50 in a manner that is consistent with that used to develop the risk-informed revision to the PTS regulations. Scoping probabilistic fracture mechanics (PFM) analyses have been performed for several hundred parameterized cool-down transients to (1) obtain insights regarding the interaction of operating temperature and pressure parameters on the conditional probability of crack initiation and vessel failure and (2) determine the limits on the permissible combinations of operating temperature and pressure within which the reactor may be brought into or out of an operational condition that remains below the acceptance criteria adopted for PTS of 1 × 10−6 failed RPVs per reactor operating year. This paper discusses the modeling assumptions, results, and implications of these scoping analyses.

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