heat release

Top PDF heat release:

Combustion heat release models of biodiesels

Combustion heat release models of biodiesels

Empirical investigations are carried out for the implementation of real-time heat release analysis that will provide feedback for adaptive control of modern diesel combustion systems. The suitability of a number of cylinder- pressure derived parameters and heat release characteristics is discussed for real-time applications. The crank angle of heat released was shown to represent a stable and robust measure of the phasing of the heat release patterns that characterize the clean combustion techniques of modern diesel engines. The experimental work has investigated the diagnosis combustion process by cylinder pressure measurement for JCB diesel engines, and engine operating conditions with the different fuels of diesel and biodiesel. The combustion process of diesel engines is usually represented by a cylinder pressure signal. The combustion profile for biodiesel fuel that is very similar to that of the baseline diesel fuel, and a similar torque is demanded from the engine. The pressure of combustion increases marginally when increasing the percentage of biodiesel. Reviews indicate that engine performance characteristics with biodiesels are similar to those with fossil diesel, which makes biodiesel fuels an alternative to help overcome the current energy and environmental crises. One of the purposes of this study was to analyze the emissions present by running biodiesel fuels and its blends on a conventional diesel engine. From the literature review it was apparent that by running a biodiesel blend fuel there would be a decrease in emissions present while a slight decrease in engine efficiency. The experiential data did confirm these claims showing decreases in almost all the emissions CO, THC and CO 2 except
Show more

7 Read more

Pasty Ranges and Latent Heat Release Modes for Sn 9Zn xAg Lead free Solder Alloys

Pasty Ranges and Latent Heat Release Modes for Sn 9Zn xAg Lead free Solder Alloys

The pasty ranges and latent heat release modes of Sn-9Zn-xAg alloys, where x varies between 0.5 and 3.5, are examined in this study. The effects of alloy composition and cooling rate on the pasty range and latent heat release modes are also investigated. A Computer Aided-Cooling Curve Analysis (CA-CCA) technique is used to determine the pasty ranges and latent heat release modes for the alloys. To comply with the requirements of CA-CCA, the heat transfer conditions of the experimental setup must closely resemble of a lumped system, in which the alloy is cooled in a uniform fashion. To confirm this, two thermocouples are inserted into the crucible where the alloy is melted and subsequently resolidified. The crucible is used with and without a covering of insulating material to obtain different cooling rates. The temperature readings show that the heat transfer conditions in the experimental setup indeed meet the requirements of a lumped system. The solid fraction versus temperature relationship ( f s -T) for the various alloy compositions and cooling rates are obtained from the temperature data through CA-CCA.
Show more

9 Read more

Heat Release Rate in a Reduced-Scale Model of a Subway Car on Fire

Heat Release Rate in a Reduced-Scale Model of a Subway Car on Fire

Abstract: The heat release rate of a subway car on fire is measured for various positions of an ignition source and simulated materials differing in combustibility by using a reduced-scale model. Although the maximum HRR value is nearly independent of the position of the ignition source, the time required to reach this value varies greatly for different ignition positions. The open area of a subway car is a key factor that determines the maximum HRR value, although material combustibility also has an effect. Finally, the HRR curve is compared with that of a fire test in a real-scale subway car.
Show more

6 Read more

Impact of a Residential Sprinkler on the Heat Release Rate of a Christmas Tree Fire

Impact of a Residential Sprinkler on the Heat Release Rate of a Christmas Tree Fire

temperature of 68 ºC (155 ºF). For a maximum coverage area of 3.7 m (12 ft) by 3.7 m (12 ft), the listed minimum water requirement is 34.1 L/min @ 58.1 kPa (9 gpm @ 8.4 psi) [17]. The water supply to the sprinkler was set to 34.1 L/min (9 gpm). The smoke alarm and the sprinkler both activated 10 seconds after ignition. The fire developed so rapidly that the temperature of the thermocouple next to the sprinkler measured approximately 500 ºC (932 ºF) just prior to activation. The thermocouple adjacent to the smoke alarm measured approximately 350 ºC (662 ºF) just prior to alarm. The heat release rate and temperatures are shown in figures 14 through 16. The rate of heat release was reduced by the activation of the sprinkler, however, the heat release rate continued to increase as the tree continued to burn. That being said, the water from the sprinkler kept portions of the tree below the point of ignition from burning and limited the flame spread on the furnishings. As a result, the compartment did not flashover and the peak heat release rate was kept to less than one third of the non-sprinklered
Show more

30 Read more

A note on latent heat release from disequilibrium phase transformations and deep seismogenesis

A note on latent heat release from disequilibrium phase transformations and deep seismogenesis

In the temperature-dependent rheological weakening model, on the other hand, shear localization occurs through ductile deformation. Consequent shear heating, arising from concentrated conversion of elastic strain energy (Regenauer- Lieb and Yuen, 1998), leads to weakening in material with temperature-dependent rheology. This further focuses addi- tional shear deformation, and such a feedback cycle leads to “adiabatic instability” as a potential mechanism for deep seismicity (Ogawa, 1987; Hobbs and Ord, 1988; Karato, 1997). Indeed, in addition to this subsolidus temperature- induced rheological weaking, such shear localization may induce partial melting (Ogawa, 1987; Karato, 1997) leading to even greater local reductions in viscosity. While there is no direct evidence of such melting in the transition zone, shear localization appears in some cases to have induced high degrees of partial melting within the lithosphere (Austrheim and Boundy, 1994; Obata and Karato, 1995; Austrheim et al., 1996; Jin et al., 1998), and frictional melting has also been suggested recently as an adjunct to deep seismicity (Kanamori et al., 1998). Local superheating arising from latent heat release due to disequilibrium transformation of metastable phases could initiate such adiabatic instability by locally depressing viscosities within the superheated zone, and consequent shear localization could induce failure be- yond the extent of the metastable material in which it was initially triggered.
Show more

6 Read more

Heat release rate estimation in laminar premixed flames using laser-induced fluorescence of CH2O and H-atom

Heat release rate estimation in laminar premixed flames using laser-induced fluorescence of CH2O and H-atom

with computations of one-dimensional freely-propagating flames. The performance of these markers is studied based on the following two aspects: the spatial accuracy of the local heat release rate and the trend in the total heat release rate with equivalence ratio. The measured trend in the spatial distribution of radicals and the deduced heat release rate agree well with the computational values. The variation in the spatially integrated heat release rate as a function of equivalence ratio is also investigated. The results suggest that the trend in the variation of the integrated heat release rate and the spatial location of heat release rate can be evaluated by either of these markers. The OH-based marker showed certain sensitivity to the chemical mechanism as compared to the H-atom based marker. Both the OH-based and H-atom based techniques provide close estimates of heat release rate. The OH based technique has practical ad- vantage when compared to the H-atom based method, primarily due to the fact that the H-atom LIF is a two-photon process.
Show more

11 Read more

Combustion Heat Release Estimation to Explore Best Blend of Mahuva Methyl Ester and Diethyl Ether as Cetane Improver

Combustion Heat Release Estimation to Explore Best Blend of Mahuva Methyl Ester and Diethyl Ether as Cetane Improver

Single zone heat release rate calculations with in cylinder heat transfer are done with the combustion pressure as an input and a comparative study is taken up with neat diesel and Mahuva methyl ester as a biodiesel with Diethyl Ether (DEE-Cetane improver). Combustion Delay period trend is assessed by the close scrutiny of the combustion pressure signatures and the combustion behavior is being assessed with the net heat release rate and cumulative heat release plots at various loads on the engine with different fuels. Present work deals with trials of Mahuva Methyl Ester (MME) and Diethyl Ether (DEE) additive blends. Various blends of MME with additive at different percentages (3%, 5%, 10%, and 15%) by volume were prepared and tested in full range of engine load. Results obtained from the study shows that 15% of additive with MME could be a better fuel in terms of combustion pressure changes and heat release. Further, the blend can be used in any existing CI engines without engine modification or fuel preheating. Mixing DEE additive with biodiesel improves the cold flow, combustion efficiency, and viscosity and reduces the engine detonation. Combustion analysis is also taken up with real vibration time waves recorded vertical on the cylinder head.
Show more

6 Read more

Heat Release Model of DI Diesel Engine: A Review

Heat Release Model of DI Diesel Engine: A Review

The basis for the modeling of the heat release is the first law of thermodynamics for an open system. Open system is that system in which the mass entering in the system and reject from the system. Assuming the cylinder charge as a single zone and using the ideal gas law, the heat release during combustion, on a crank angle basis is given by [1]:

7 Read more

Flammability of natural plant and animal fibers: a heat release survey

Flammability of natural plant and animal fibers: a heat release survey

The results in this survey paper clearly show that within each group, plant and animal fibers have different heat releases when they burn, and therefore, cannot all be considered to be the same from a flammability perspective when used as reinforcement for composites or as fibers in textiles. The differences in heat release are due to a mix of chemical and physical structural differences, including natural impurities, in the fibers based upon how each plant or animal “constructs” the fiber from various cellulose and polypeptide structures. The effect of fiber processing on flammability can be notable, and it is important to understand how the fibers are processed and what impurities may be present. To better connect chemical structure to the observed flammability differences, more detailed chemical analysis of the fibers is recommended, especially to help understand how processing of the fibers affects flammability, as was observed with the study of cotton fibers in particular, although it is well known that trace mineral impurities are significant factors.. Additionally, it should be pointed out that these differences in fiber heat release rate at the milligram scale may not always translate into larger structures where fiber weave or areal density will have notable effects on flame spread and material flammability. Furthermore, the “fire model” present in the MCC of initial sample pyrolysis under nitrogen followed by ignition and combustion of volatiles does not reflect the ignition and burning of a fabric or composite in a simple ignition/flame spread test although
Show more

20 Read more

Influences of cylinder wall temperature on heat release during compression period

Influences of cylinder wall temperature on heat release during compression period

Abstract Compression period in a diesel engine is generally seen as initial characteristics before injection into combustion chamber. A free-piston type rapid compression machine (RCM) has been designed simulate the combustion phenomena in order to observe the chemical and physical kinetics studies at elevated pressures and temperatures. Purpose of this study is to clarify the effects of wall cylinder temperature on air heat release, especially during compression period. This method can a light piston is pneumatically shot and gets hammered in stopper at compression end. Measurements were made on a light piston compress in a rapid compression machine (RCM) with intended to simulate the actual compression period related phenomena. During this phenomena, the ambient temperature influences from the cylinder wall temperature has appear beneficial for the biodiesel fuel premixing and achieving best mixture preparation There are three tests will used to investigate the effects of the variant temperature of wall cylinder during compression period. Results show high temperature on cylinder wall will be effects decrease during temperature drop after compression stroke. The new characteristics rapid compression machine (RCM) is to develop and analyse before combustion process.
Show more

5 Read more

An Analysis of Furniture Heat Release Rates by the Nordtest

An Analysis of Furniture Heat Release Rates by the Nordtest

88 Figure 8.74 shows the predicted based on the Cone Calorimetry tests conducted both at CSIRO and the University of Canterbury vs the measured CSIRO full-scale Furniture Calorimeter tes[r]

156 Read more

Fluid And Heat Flow Performance In Heat Exchanger

Fluid And Heat Flow Performance In Heat Exchanger

In an automobile, fuel and air produce power within the engine through combustion. Only a portion of the total generated power actually supplies the automobile with power, the rest is wasted in the form of exhaust and heat. If this excess heat is not removed, the engine temperature becomes too high which results in overheating and viscosity breakdown of the lubricating oil, metal weakening of the overheated engine parts, and stress between engine parts resulting in quicker wear, among other things.

24 Read more

Release 175 Graphics Drivers Release Notes

Release 175 Graphics Drivers Release Notes

NVIDIA, the NVIDIA logo, 3DFX, 3DFX INTERACTIVE, the 3dfx Logo, STB, STB Systems and Design, the STB Logo, the StarBox Logo, NVIDIA nForce, GeForce, NVIDIA Quadro, NVDVD, NVIDIA Person[r]

66 Read more

Release 186 Graphics Drivers Release Notes

Release 186 Graphics Drivers Release Notes

NVIDIA, the NVIDIA logo, 3DFX, 3DFX INTERACTIVE, the 3dfx Logo, STB, STB Systems and Design, the STB Logo, the StarBox Logo, NVIDIA nForce, GeForce, NVIDIA Quadro, NVDVD, NVIDIA Person[r]

39 Read more

Version 2015 Release 1 Release Notes

Version 2015 Release 1 Release Notes

In your business, there may be a wide variety of events that can require an adjustment to your general ledger. For example, you may need to record credits for non-operational income, such as interest income that your company receives through investments. Conversely, you may need to record debits for bad debts — money owed to your business that you do not expect to collect. Prior to this release, your options for recording these various adjustments were limited. A typical strategy would be to record all adjustments as journal entries. However, when you rely solely on the journal entry record, all of these varying transactions are grouped together in a single list view. Moreover, when employees enter journal entries, they have limited choices for distinguishing one type of journal entry from another.
Show more

75 Read more

Version 2014 Release 1 Release Notes

Version 2014 Release 1 Release Notes

With Version 2014 Release 1, you can bulk process email or faxes for multiple transactions at one time. When you process bulk transactions you are able to attach any message or use scriptable templates. This feature is useful when you want to send reminder email related to multiple transactions for which payments have not been received. Optionally, you can use criteria to filter the transaction list, then check the box in the Select column next to transactions requiring the bulk email or fax. You can also use the To Be Faxed option on a Mass Update to bulk sending of faxes.

162 Read more

Version 2015 Release 2 Release Notes

Version 2015 Release 2 Release Notes

Prior to this release, NetSuite deployed custom domains two times a month. Procedures have been automated to minimize the time between the uploading of SSL certificate and the deployment of your custom domain. Domains are now deployed many times each day. You will be notified by email when your domain goes live. Before uploading your SSL certificates, ensure you have completed all the necessary steps in Prerequisites for Setting Up a Custom Checkout Domain in NetSuiteand in Setting Up a Secure Checkout Domain in NetSuite.

99 Read more

Release Notes for VPN Client, Release 4.0.1

Release Notes for VPN Client, Release 4.0.1

This problem might not occur if the Digital Certificate you are using is small enough, but this is only in rare cases. This fragmentation problem happens with the D-Link DI-704 and many other Cable/DSL routers on the market. We have been in contact with a few of these vendors to try to resolve the issue. Testing with the VPN Client Release 3.1 indicates that VPN Client connections using Digital Certificates can be made using the following Cable/DSL routers with the following firmware:

72 Read more

APPLICATIONS OF AN HEAT PIPE HEAT EXCHANGER IN THE RECOVERY OF WASTE HEAT FROM URBAN WASTEWATERS

APPLICATIONS OF AN HEAT PIPE HEAT EXCHANGER IN THE RECOVERY OF WASTE HEAT FROM URBAN WASTEWATERS

In the present study the heat source is of low temperature, so heat transfer is carried out only by free convection. Although there are many applications where waste heat is recovered from municipal wastewater (Kalberer, 2007), there is no report on the effectiveness of heat pipe in the process. The purpose of this research is to determine the efficiency of Q-Pipe heat pipe heat exchanger for waste heat recovery from municipal wastewater.

7 Read more

A REVIEW ON HEAT TRANSFER ENHANCEMENT IN HEAT EXCHANGER

A REVIEW ON HEAT TRANSFER ENHANCEMENT IN HEAT EXCHANGER

This review paper discuses the considerable experimental work which has been done on heat transfer augmentation through internal inserts in circular tubes. Some kind of internal insert like helical tap insert, wire mesh tape insert etc., placed in the flow passage of a tube to augment the heat transfer rate. This inserts mixes the bulk flow well and therefore performs better in laminar flow. However in laminar flow the thermal resistance is not limited to a thin region. Hence, it is concluded that inserts are effective in laminar flow. Turbulent flow is effective up to a certain Reynolds number because more Reynolds number block the flow and increases the pressure drop which is the cause of lower heat transfer. Turbulent flow is more frequently encountered than laminar flow so a great change of local heat transfer rate in separated flow region is achieved and considerable heat transfer augmentation may result up to reattachment region.However, the question of scalability remains unanswered because of practical difficulties in experimental work. There is a need of analyzing dynamics similarities amongst the geometrical similarities on large scale model covering industrial application. Further research is required to be conducted at a large scale on considerable range of curvature ratio, low range of curvature ratio, low range of Prandtl number and low Reynolds numbers, temperature etc.
Show more

6 Read more

Show all 10000 documents...