Hydrogen Gas Generation in Water Heat Pipes

1978 ◽  
Vol 100 (3) ◽  
pp. 313-318 ◽  
Author(s):  
G. F. Pittinato
Keyword(s):  
Stainless Steel ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Hydrogen Gas ◽  
Gas Generation ◽  
Inconel 600 ◽  
430 Stainless Steel ◽  
Incoloy 800 ◽  
Isothermal Operation ◽  
Short Time

Water heat pipes were fabricated from 316, 347, and 430 stainless steel, Monel 400, CDA 715, Inconel 600, and Incoloy 800. All of these materials generated varying amounts of hydrogen gas during the first few days of operation. However, as the heat pipes continued to operate, the amount of gas in each heat pipe, excluding 430 stainless steel, decreased by permeating through the heat pipe walls. Inconel 600 appeared to be the most acceptable material for water heat pipes by returning to isothermal operation over a short time period. An equation based on a diffusion dependent mechanism was developed that predicts heat pipe performance recovery rates.

Metallic Mesh as Capillary Structure Applied in Heat Pipe Heat Exchanger for Heat Recovery

2014 ◽  
Vol 1082 ◽  
pp. 309-314 ◽  
Author(s):  
Diogo L.F. Santos ◽  
Larissa S. Marquardt ◽  
Paulo H.D. Santos ◽  
Thiago Antonini Alves
Keyword(s):  
Stainless Steel ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Working Fluid ◽  
Capillary Structure ◽  
Porous Wick ◽  
Metallic Mesh ◽  
Heat Loads ◽  
Pipe Heat

This work presents a theoretical and experimental analysis of a heat exchanger assisted by five heat pipes made of copper with a metallic mesh 100 of stainless steel which was used as capillary structure. All heat pipes used water as the working fluid and were designed based on the capillary limit model. The heat pipes were developed and tested under heat loads varying from 20 to 50 W before application into the heat exchanger. The theoretical and experimental results were compared and all heat pipes worked satisfactorily. Thereafter, it is presented the development of heat pipe heat exchanger which was tested under heat loads varying from 100 to 250 W. The highest temperature measured on the external surface of the heat pipes was 90 oC and the heat exchanger thermal efficiency varied from 74 to 80%. It is showed that the use of a stainless steel mesh as a porous wick was proved to work successfully in heat pipes.

Passivation and Performance of Inorganic Aqueous Solutions in a Grooved Aluminum Flat Heat Pipe

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Michael J. Stubblebine ◽  
Ivan Catton
Keyword(s):  
Aqueous Solutions ◽  
Heat Pipe ◽  
Operating Performance ◽  
Heat Pipes ◽  
Hydrogen Gas ◽  
Working Fluid ◽  
Heating Section ◽  
And Performance ◽  
Aluminum Plates ◽  
Flat Heat Pipe

Aluminum heat pipes have traditionally been incompatible with water and water-based fluids because they quickly react to generate noncondensable hydrogen gas (NCG). Two different inorganic aqueous solutions (IAS) are tested in a flat heat pipe (FHP). Grooved aluminum plates were used as the heat pipe wick and the tests were run with the heating section raised above the condenser. Compatibility between the working fluid and the aluminum heat pipe was established by running the device to dryout and observing thermal resistance results along the way. De-ionized (DI) water was also tested, as a baseline for comparison, to establish that it did indeed fail as expected. Operating performance of each mixture was obtained from zero heat input until dryout was reached for two angles of inclination. The data suggest that both IAS mixtures are compatible with aluminum heat pipes and exhibit performance similar to that of a copper and water heat pipe. It is demonstrated that IAS and aluminum heat pipes show potential for replacing existing copper and water devices for some applications and provide alternative options for heat pipe designers who value both the thermophysical property advantages of water and reduced weight of aluminum devices.

Numerical Analysis of a Metal Hydride Reactor With Embedded Heat Pipes to Enhance Heat Transfer Characteristics

2009 ◽  
Author(s):  
Joon Hong Boo ◽  
Young Hark Park ◽  
Masafumi Katsuta ◽  
Sang Chul Bae
Keyword(s):  
Thermal Conductivity ◽  
Numerical Analysis ◽  
Heat Pipe ◽  
Metal Hydride ◽  
Three Dimensional ◽  
Heat Pipes ◽  
Thermal Control ◽  
Hydrogen Gas ◽  
Outer Diameter ◽  
Reactor Model

Numerical analysis was conducted for a heat pipe application in a metal hydride (MH) reactor for hydrogen gas storage. The hydriding and dehydriding characteristics of MH strongly depend on temperature and pressure. Due to its extremely low thermal conductivity however, it is very difficult to control the temperature of MH, especially when it is of vast bulk as in an MH reactor. This study deals with heat pipes embedded into the MH to increase the effective thermal conductivity of the system and thus to enhance the thermal control characteristics. The existing model was a brine-tube type MH reactor having cylindrical container with outer diameter of 76 mm and length of 1 m, which was partially filled with 8 to 10 kg of MH material. The hydriding and dehydriding processes occur at 10°C and 80°C, respectively. The heat-pipe type reactor model replaced the brine tubes and channels with copper-water heat pipes of the same dimensions. Three-dimensional numerical analysis predicted that the heat-pipe type MH reactor model enhanced thermal performance with faster response to the change of boundary conditions and higher degree of isothermal characteristics. Discussion is presented based on the numerical results of the two models compared with experimental results.

Passivation and Performance of Inorganic Aqueous Solutions in a Grooved, Aluminum Flat Heat Pipe

2013 ◽  
Author(s):  
Michael Stubblebine ◽  
Ladan Amouzegar ◽  
Ivan Catton
Keyword(s):  
Aqueous Solutions ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Hydrogen Gas ◽  
Working Fluid ◽  
Aerospace Applications ◽  
Heating Section ◽  
And Performance ◽  
Aluminum Plates ◽  
Flat Heat Pipe

Aluminum heat pipes have traditionally been incompatible with water and water-based fluids because they quickly react with the casing to generate non-condensable hydrogen gas (NCG). The NCGs inhibit the operation of evaporation and condensation based devices, eventually plugging the condenser end of the heat pipe. The heat pipe is then unable to remove heat from the condenser and the device fails. Terdtoon [1] found that these events often happen so rapidly between aluminum and water that measurements cannot even be taken. The present work tested two different, patented inorganic aqueous solutions (IAS) in a flat heat pipe setup. Grooved aluminum plates were used as the heat pipe wick and the tests were run with the heating section raised above the condenser. Compatibility between the working fluid and aluminum heat pipe was established by running the device to dryout and then reducing the heat flux to check for hysteresis. De-ionized water (DI water) was also tested, as a baseline, to establish that it did indeed fail as expected. Operating performance of each mixture was obtained from zero heat input until dryout was reached for multiple angles of inclination. The data show that both IAS mixtures are compatible with aluminum heat pipes and exhibit performance similar to that of a copper and water heat pipe. IAS and aluminum heat pipes could replace existing copper and water devices and deliver similar performance while reducing overall weight by more than three times. An IAS and aluminum heat pipe could also replace existing aluminum and ammonia combinations, currently favored in aerospace applications, to allow for increased performance and a larger operating temperature range while maintaining low device weight.

Stress Corrosion Cracking and Anodic Behavior of AISI 304 Stainless Steel, Inconel 600, and Incoloy 800 Straining in Boiling NaOH Solutions

CORROSION ◽  
1978 ◽  
Vol 34 (12) ◽  
pp. 413-418 ◽  
Author(s):  
Y. S. PARK ◽  
J. R. GALVELE ◽  
A. K. AGRAWAL ◽  
R. W. STAEHLE
Keyword(s):  
Stainless Steel ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
304 Stainless Steel ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Inconel 600 ◽  
Naoh Solution ◽  
Incoloy 800 ◽  
Electrode Technique

Abstract The straining electrode technique was used to evaluate the stress corrosion cracking (SCC) susceptibility of AISI 304 stainless steel in 20N NaOH solution, and of Inconel 600 Alloy and Incoloy 800 Alloy in boiling 17.5N NaOH solution. The crack propagation rate estimated from the straining experiments correlated well with failure time measurements from previous constant load experiments. It was found that the straining electrode technique is a useful method for estimating, through short term experiments, parameters like crack propagation rate, crack morphology, and repassivation rate, as a function of the electrode potential.

The Application of Heat Pipes for Fruit Juice Pasteurizing Machine

2012 ◽  
Vol 550-553 ◽  
pp. 3140-3144
Author(s):  
Sawanit Aichayawanich ◽  
Sirasa Jengsooksawat
Keyword(s):  
Stainless Steel ◽  
Temperature Distribution ◽  
Heat Pipe ◽  
Orange Juice ◽  
Fruit Juice ◽  
Heat Pipes ◽  
304 Stainless Steel ◽  
Internal Diameter ◽  
Test Tank ◽  
Heating Device

This research was aim to apply heat pipe in the small pasteurizing machine for fruit juice process. The orange juice was used as the sample. The container of the pasteurizing machine was made from 304 stainless steel with 1.5 millimeter of thickness, 300 millimeter of inside diameter, and 374 millimeter high, with 20 liters capacity. In order to control the temperature distribution in the test tank, four heat pipes, that made from same material, were used as heating device that heated from LPG gas. The heat pipe had 0.8 millimeters of thickness, 25millimeter of internal diameter, and the length of 650 millimeters. The result was found that the pasteurizing machine can be pasteurized the orange juice as 88 degree celsius with 32.5 minutes of come up time. The temperature distribution of the orange juice in the tank was  0.5 degree celsius.

Gas Generation Behavior of Transuranic Waste Under Disposal Conditions

1999 ◽  
Vol 556 ◽  
Author(s):  
Ryutaro Fujisawa ◽  
Tetsunari Kurashige ◽  
Yusuke Inagaki ◽  
Muneaki Senoo
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Initial Period ◽  
Hydrogen Gas ◽  
Generation Rate ◽  
Gas Generation ◽  
Geological Disposal ◽  
Synthetic Groundwater ◽  
Gas Generation Rate ◽  
Transuranic Waste

AbstractThe generation of hydrogen-gas from metallic waste is an important issue for the safety analysis of geological disposal facilities for transuranic (TRU) radioactive waste in Japan. The objective of this study is to clarify the gas-generation behavior of stainless steel and carbon steel in non-oxidizing alkaline synthetic groundwater (pH 12.8 and 10.5) at 30 °C simulating geological disposal environments. At pH 12.8, the observed gas-generation rate from stainless steel in the initial period of immersion was 1.0 × 102 Nml/m2/y and 1.0 × 10 Nml/m2/y after 200 days (N represents the standard state of gas at 0 °C and 1 atm). At pH 10.5, gas generation was not observed for 60 days in the initial period. At 60 days, the gasgeneration observed was 5.0 × 10 Nml/m2/y. After 250 days, the gas-generation rate approaches zero. At pH 12.8, the observed gas generation rate of carbon steel in the initial period of immersion was 1.5 × 102 Nml/m2/y and the gas generation rate began to decrease after 200 days. After 300 days, it was 25 Nml/m2/y. At pH 10.5, the gas generation rate in the initial period was 5.0 × 102 Nml/m2/y and was 1.0 × 10 Nml/m2/y after 200 days.

Selective Corrosion of brazed joint between BNi-2 filler metal and stainless steel 316

1996 ◽  
Vol 54 ◽  
pp. 218-219
Author(s):  
H. S. Kim ◽  
R. U. Lee
Keyword(s):  
Stainless Steel ◽  
Filler Metal ◽  
Surface Preparation ◽  
Optical Microscope ◽  
Heating Element ◽  
Incomplete Fusion ◽  
Atmospheric Conditions ◽  
Leak Test ◽  
High Temperature Side ◽  
Inconel 600

A heating element/electrical conduit assembly used in the Orbiter Maneuvering System failed a leak test during a routine refurbishment inspection. The conduit, approximately 100 mm in length and 12 mm in diameter, was fabricated from two tubes and braze-joined with a sleeve. The tube on the high temperature side (heating element side) and the sleeve were made of Inconel 600 and the other tube was stainless steel (SS) 316. For the filler metal, a Ni-Cr-B brazing alloy per AWS BNi-2, was used. A Helium leak test spotted the leak located at the joint between the sleeve and SS 316 tubing. This joint was dissected, mounted in a plastic mold, polished, and examined with an optical microscope. Debonding of the brazed surfaces was noticed, more pronounced toward the sleeve end which was exposed to uncontrolled atmospheric conditions intermittently. Initially, lack of wetting was suspected, presumably caused by inadequate surface preparation or incomplete fusion of the filler metal. However, this postulation was later discarded based upon the following observations: (1) The angle of wetting between the fillet and tube was small, an indication of adequate wetting, (2) the fillet did not exhibit a globular microstructure which would be an indication of insufficient melting of the filler metal, and (3) debonding was intermittent toward the midsection of the sleeve.

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