Jacket Water Temperature Research Articles

Technology of dry extract from the <i>Filipendula ulmaria</i> (L.) Maxim. and preliminary assessment of its safety profile

Introduction. Medicines of natural origin have advantages over synthetic drugs and occupy a significant share in the assortment of pharmacies. Filipendula ulmaria (L.) Maxim., characterized by a chemical composition rich in phenolic compounds and various types of biological activity has the potential in terms of the development of new herbal medicines. In an in vivo experiment, F. ulmaria extract showed immunomodulatory, anti-inflammatory, osteogenic activity and effectively stimulated myelopoiesis in conditions of microbial damage of bone tissue.Aim. Development of an optimal technology for obtaining dry extract of F. ulmaria by remaceration and investigation of its аcute toxicity.Materials and methods. The technology of extract was developed in a laboratory reactor equipped with a water heater jacket and a stirrer. The content of flavonoids was determined by differential spectrometry. Flowability was determined on a flowability tester for powders and granules, bulk density was determined on a bulk density tester for powders and granules, moisture content was developed on a moisture content analyzer. Acute toxicity was determined on Wistar rats.Results and discussion. The dry extract of F. ulmaria, obtained using 70 % ethanol by remaceration, is effective in conditions of microbial damage of bone tissue and bone marrow, which determined the choice of extragent and the type of extract. The optimal parameters for obtaining the extract were determined (three-fold maceration at a water jacket temperature of 80 °C, the ratio of raw materials to extragent 1 : 14, time 30 min), its main technological characteristics were determined and a wet granulation method for improving them was proposed. In the study of acute toxicity of the extract, according to the results of toxicometry for 14 days after administration and necropsy data, the studied extract was classified as low-toxic substance.Conclusion. The dry extract of F. ulmaria, obtained by remaceration using 70 % ethanol, has specific activity in conditions of microbial damage to bone tissue. Optimal extraction parameters allow to increase the yield of target components, it is advisable to improve the technological parameters of the extract by wet granulation. The assessment of the safety profile of the dry extract from F. ulmaria, along with its high biological activity, provides a perspective for its further study and implementation into medical practice.

EFEK KONFIGURASI BAFFLE PADA HEAT EXCHANGER TYPE SHELL AND TUBE SEBAGAI PEMANAS BAHAN BAKAR BIODIESEL B20

B20 is a fuel that is widely used for combustion systems in diesel engines, especially in Indonesia. Apart from having the advantages, biodiesel B20 also has various disadvantages that affect the performance of diesel engines such as those that have a higher flash point than diesel so that biodiesel is more difficult to burn and has a high viscosity which causes less good atomization of fuel and eventually causes deposits in combustion chamber. One or the solution to the problem is that it can be done carefully. The aim of this research is to make a Shell and Tube Heat Exchanger (STHE) by including the insulation in it to improve the heat exchange performance. The method applied in this research is an experiment by testing the performance of the heat exchanger using a cooling water jacket. Some of the equipment used is a diesel engine from the Mitsubishi Diesel Engine, Type 4d35, 4 cylinder, 75 HP. Data were collected at a constant rotation of 1500 rpm at no load. The results showed that the higher the cooling water temperature of the jacket, the higher the biodiesel temperature. With a cooling water jacket temperature of 83oC, it can heat biodiesel at 74.8oC. Keywords : B20 Fuel Oil; Diesel Engine; Heater; Heat Recovery; Jacket Cooler

An Economical and Precise Cooling Model and Its Application in a Single-Cylinder Diesel Engine

The cooling system is an important subsystem of an internal combustion engine, which plays a vital role in the engine’s dynamical characteristic, the fuel economy, and emission output performance at each speed and load. This paper proposes an economical and precise model for an electric cooling system, including the modeling of engine heat rejection, water jacket temperature, and other parts of the cooling system. This model ensures that the engine operates precisely at the designated temperature and the total power consumption of the cooling system takes the minimum value at some power proportion of fan and pump. Speed maps for the cooling fan and pump at different speeds and loads of engine are predicted, which can be stored in the electronic control unit (ECU). This model was validated on a single-cylinder diesel engine, called the DK32. Furthermore, it was used to tune the temperature of the water jacket precisely. The results show that in the common use case, the electric cooling system can save the power of 255 W in contrast with the mechanical cooling system, which is about 1.9% of the engine’s power output. In addition, the validation results of the DK32 engine meet the non-road mobile machinery China-IV emission standards.

Numerical Analysis of the Thermal Performance in Traditional and Developed Shapes of Thermosyphon

In recent years, the research in renewable energy is remarkably increased to reduce the reliance on fossil fuels. Solar energy took the lead among the other sources of renewable energy due to its availability everywhere and the feasibility of its use for various circumstances. Thermosyphon is one of the most successful systems for solar energy conversion. In the present study, a CFD code is employed to analyze the natural convection phenomenon which is inherent in the performance of a thermosyphon system. A steal pipe of 25 mm internal diameter and 1250 mm length is considered as the condenser of the thermosyphon. Water jacket is used to cool the condenser with an internal diameter that is five times that of the condenser. Two types of pipes are considered in the present study, namely; straight and helical pipes. The case of helical pipe assumes five different numbers to turns, which are; 10, 20, 30, 40 and 45 turns. A solar heat flux of 500 W/m2 and above is used in the analysis. The results obtained from the numerical analysis showed that the helical pipe is more efficient than the straight pipe in heating the water inside the condenser jacket for the same operating conditions. The ratios of increase in jacket water temperature of the five cases of the helical pipe to that of the straight pipe were 23.8%, 36.5%, 42.1%, 45.3% and 46.2%, respectively.

Identification of Chemical Reactor Plant’s Mathematical Model

This work presents a solution of the identification problem of chemical reactor plant’s mathematical model. The main goal is to obtain a mathematical description of a chemical reactor plant from experimental data, which based on plant’s time response measurements. This data consists sequence of measurements for water jacket temperature and information about control input signal, which is used to govern plant’s behavior.

Role of heat pipes in improving the hydrogen charging rate in a metal hydride storage tank

Metal hydrides can store hydrogen at high volumetric efficiencies. As the process of charging hydrogen into a metal powder to form its hydride is exothermic, the heat released must be removed quickly to maintain a rapid charging rate. An effective heat removal method is to incorporate a heat exchanger such as a heat pipe within the metal hydride bed. In this paper, we describe a two-dimensional numerical study to predict the transient heat and mass transfer in a cylindrical metal hydride tank embedded with one or more heat pipes. Results from a parametric study of hydrogen storage efficiency are presented as a function of storage tank size, water jacket temperature and its convective heat transfer coefficient, and heat pipe radius and its convective heat transfer coefficient. The effect of enhancing the thermal conductivity of the metal hydride by adding aluminum foam is also investigated. The study reveals that the cooling water jacket temperature and the heat pipe's heat transfer coefficient are most influential in determining the heat removal rate. The addition of aluminum foam reduces the filling time as expected. For larger tanks, more than one heat pipe is necessary for rapid charging. It was found that using more heat pipes of smaller radii is better than using fewer heat pipes with larger radii. The optimal distribution of multiple heat pipes was also determined and it is shown that their relative position within the tank scales with the tank size.

Experimental investigation of thermosyphon loop thermal performance

This paper presents the experimental investigation of a two-phase closed loop. The experimental setup consists of an evaporator and a condenser connected by two insulated tubes. Using water as a working fluid, the experiments were conducted to evaluate the performance of a thermosyphon: the effects of fill charge ratio, the condenser jacket coolant inlet temperature and the mass flow rate. Finally, the results show that the optimal fill charge ratio is between 7% and 10%, the cooling system has the optimal performance when controlling the condenser jacket water temperature and flow rate at 5°C and at 0.7l/min respectively. System, loop, evaporator, vapor line, condenser, and liquid line thermal resistances analysis is directed additionally to the pressure and temperature evolutions for the better understand of the main parameters affecting the cooling system performance.

Design and Analysis of in-Wheel Permanent Magnet Synchronous Motor Cooling System of Mining Dump Truck

In-wheel motor is an important power unit of electric drive mining trucks, a variety of dynamic performance and thermal issues have important impacts on the whole vehicle performance. In this paper, a model of permanent magnet brushless DC motor (BLDC) cooling system with water-cooled stator structure of electric drive mine dump truck is built. Considering the actual cooling systems, the author modeled the bldc motor and completed the electromagnetic simulation with ansoft software to determine the motor heat source and boundary conditions. This paper simulates the cooling water jacket temperature field with fluent software, and finally validated the feasibility of the design of the motor and its cooling system by experiments.

A PTR-MS-Based Protocol for Simulating Bread Aroma During Mastication

The sampling parameters to simulate retronasal aroma during the mastication of white bread has been optimized using a retronasal aroma simulator (RAS) to compare the retronasal bread aroma with the conventional headspace aroma. The volatile composition in breath was compared with that in the effluent from a RAS using proton transfer reaction mass spectrometry, and the optimized RAS parameters were as follows: 2.5 g of bread sample, 250 mL of buffer, 1 L/min of N2 gas stream, 350 rpm of rotating speed, and 38 °C of water jacket temperature. The increased sensitivity and high reproducibility of RAS enabled detailed measurements of flavor release in the mouth during the mastication of bread. The simulated retronasal aroma was compared with the conventional headspace aromas by gas chromatography/olfactometry (GC/O), and the results demonstrated that the caramel note odorant of 2,5-dimethyl-4-hydroxy-3(2H)-furanone was found to show the highest contribution to the headspace aroma; however, it showed little contribution to the simulated retronasal aroma. These differences appeared to be caused by the volume of buffer added in RAS experiments. The odorant concentrations in the RAS effluent were found to decrease with the increase of the buffer volume, and the decreasing rates appeared to be associated with the chemical types of odorants. Flavor release of typical odorants in a RAS was measured at various ratios of buffer volume, and the results indicated that flavor release in mouth appeared to be influenced by the physicochemical properties of odorants. The results would help flavor chemists to make better prediction of bread aroma in mouth during the mastication.

The thermodynamics of high shear blending

As a key constituent in many aerosol powder formulations, the properties of inhaled lactose greatly influence the overall performance of the pharmaceutical powder in inhalers. The interparticle forces defining pharmaceutical performance are markedly affected by the energy input during the high shear blending process. By conducting a number of lactose blending experiments in a small-scale pharmaceutical high shear blender, heat generation in lactose during blending was studied and shown to be consistently predictable. Experiments were then conducted in a larger high shear blender to quantify the energy input into powder using an energy balance equation. A set of relations were developed requiring only the powder temperature and jacket water temperature to approximate energy input into lactose at a given impeller speed and blend time in a high shear blending process. Additionally, this study sets out to substantiate the assumptions made in the proposed energy balance model. These experiments could not identify all possible sources of error; however, evidence is presented suggesting that energy input due to impeller shaft heating is negligible. As a result, the set of relations should be applicable for any high shear blender, given a constant blade size and shape. This analysis of powder heating with respect to blending parameters could be applied to tune blending parameters to minimize powder heating and the resulting change in powder properties. These experiments have provided the framework to understand power input in high shear blending for a range of blend parameters.

Development of an experimental prototype of an integrated thermal management controller for internal-combustion-engine-based cogeneration systems

As a kind of distributed energy system, internal-combustion-engine-based cogeneration system is attracting increasing attentions for its environmental friendly and economic qualities. Some problems are encountered in the application, such as jacket water temperature control and the recovery/management of waste heat. To solve these problems, the concept of “integrated thermal management controller” (ITMC) is presented in this paper. Experimental prototype is established to verify its operation principle. Experimental results show that the prototype can effectively control the temperature in variable working conditions. Water/R22 is a good combination of working fluid/non-condensable gas in temperature control. The regulation of hot water flow rate is an effective method to adjust the heat allocated to heat consumer.

Ignition and boost effects on large-bore engine in-cylinder heat transfer

One cylinder of the Colorado State University large-bore test engine was instrumented with fast-response surface thermocouples for heat-transfer analysis. Probes were installed at several locations progressively farther from the ignition source and their outputs were recorded along with combustion pressure using a high-speed data-acquisition system. The engine was operated with two different ignition methods and the manifold boost pressure and cylinder jacket water temperature (JWT) were varied. The recorded surface temperature data were processed to calculate in-cylinder heat transfer. Combustion initiated with a screw-in type pre-combustion chamber resulted in significantly different characteristics than that initiated by a conventional spark plug. The differences in peak heat-flux value could likely be attributed to flame quench distance. Differences in other portions of the cycle could have been caused by significantly increased flame velocities associated with the pre-chamber jet. Increasing boost pressure from 25 to 54 kPa decreased peak heat-flux values about 20–30% and steady-state values about 13%. Increasing JWT 14 K had an insignificant effect on heat flux and combustion pressure.

Thermoregulatory responses to acute heat loads in the FOK rat.

FOK is an inbred rat strain with a genotypic adaptation to hot environments. The present study investigated the mechanism of the high heat tolerance of the FOK rat. Male FOK and WKAH rats were used. They were loosely restrained and placed individually in a direct calorimeter with an ambient temperature of 24 degrees C. Their hypothalamic temperature, evaporative and non-evaporative heat loss and heat production were measured. After thermal equilibrium had been attained, the rats were warmed for 30 min with a chronically implanted intraperitoneal electric heater (internal heating). At least 90 min after the heating, the jacket water temperature surrounding the calorimeter chamber was gradually raised from 24 degrees C to 36 degrees C in 80 min (external warming). During the internal heating, changes in the thermoregulatory parameters did not differ between the groups. During the external warming, the evaporative heat loss of the FOK rat was significantly greater than that of the WKAH rat, while changes in nonevaporative heat loss and heat production did not differ between the groups. The results suggest that in the FOK rat, the improved heat tolerance is attributable to an enhanced evaporative heat loss response, but not to a facilitation of nonevaporative heat loss or of metabolic depression.

Temperature regulation during acute heat loads in rats after short-term heat exposure

Eleven rats were kept at an ambient temperature of 33.5 degrees C (HC) for 4-5 consecutive days, 9 additional rats were subjected to 33.5 degrees C for approximately 5 h daily (HI) for the same period, and 12 controls (Cn) were kept at 24 degrees C. After the exposure, the rats were placed in a direct calorimeter, where the wall temperature was set at 24 degrees C, and subjected to direct internal heating (6.2 W.kg-1, 30 min) through an intraperitoneal electric heater. After the first heat load and when thermal equilibrium had been attained again, the rats were subjected to indirect external warming by raising the jacket water temperature surrounding the calorimeter from 24.0 to 38.8 degrees C in 90 min. Hypothalamic (Thy) and colonic temperatures (Tco), evaporative and nonevaporative heat loss, and metabolic heat production (M) before the acute heat loads did not differ among the groups. During heat loads, the latent times for the onsets of the rises in tail skin temperature and evaporation were significantly longer, and Thy and Tco at the start of increases in heat losses tended to be higher, in the HC than in the Cn. M significantly decreased in all groups, but the magnitude and duration of reduction in M were significantly greater in the HC than in the Cn. There were no differences between the thermoregulatory responses to heat loads of the HI and Cn. These results suggest that in HC the threshold core temperature for heat loss response and the upper critical temperature have already shifted to a higher level and that HC respond to heat stress more strongly with the reduction of M than Cn. Short-term intermittent heat exposure had little effect on the thermoregulatory mechanisms in rats.

Thermoregulatory responses to acute body heating in rats acclimated to continuous heat exposure

Thermoregulatory responses to an acute heat load with intraperitoneal heating (IH) or indirect external warming (EW) by increasing ambient temperature (Ta) were investigated with direct and indirect calorimetry in rats acclimated to environments of 24.0 degrees C (Cn), 29.4 degrees C (H1), and 32.8 degrees C (H2) for greater than 15 days. The rats were placed in a direct calorimeter where the air temperature was maintained at 24 degrees C for the initial 3 h. IH was then made for 30 min through an electric heater implanted chronically (6.5 W.kg-1) in the peritoneal cavity, and EW was performed by raising the jacket water temperature surrounding the calorimeter from 24 to 39 degrees C (0.19 degrees C.min-1). Hypothalamic (Thy) and colonic temperature immediately before the start of the heat load tended to be higher as the acclimation temperature increased. During IH, the threshold Thy for the tail skin vasodilation (Tth) was significantly higher in H2 than in Cn rats. During EW, however, there was no difference in Tth between the groups. Metabolic heat production (M) was slightly suppressed during IH and significantly depressed only in H2 rats. During EW, M was suppressed in all the groups. The magnitude and duration of suppression were greater in H2 rats than in the other two groups. The responses in nonevaporative heat loss and thermal conductance (C) to the rise in Thy did not differ among the three groups during IH. According to the rise in Thy, however, there was a greater C increase in H2 than in Cn and H1 rats during EW.(ABSTRACT TRUNCATED AT 250 WORDS)

Calibration and performance of a small animal gradient layer calorimeter box

Calorimetry, using the gradient layer technique, has become well established in the study of energy metabolism. The use of a commercially constructed gradient layer box within a calorimetry system designed to measure directly and indirectly the metabolic sequelae of thermal injury in rats, is described. Variations in the signal output were discovered. These were found to be dependent upon: (a) stability of the ambient temperature (b) stability of the gradient layer box water jacket temperature (c) position and size of the calibrating heat source.

Studies of the effects of water on gasoline engine wear at low temperature

Wear of a cold-running gasoline engine was measured by use of a radioactive piston ring and also by using a neutron activation analysis of oil for iron content. These measurements showed wear to increase greatly when jacket water temperature was reduced, when water was added to the crankcase oil, or when fuel hydrogen content was increased. A tentative explanation of these effects is proposed in which liquid water in the oil is assumed to act as a collector of the acids which cause cold wear. Water is alternately condensed when cylinder pressures are high and reevaporated when cylinder pressures are low. The average amount of liquid water in the oil, and hence also the wear rate, depends upon the relative magnitudes of condensation and re-evaporation.

An isothermal calorimeter with sample temperature control

This paper describes an isothermal calorimeter using an improved method for controlling the sample temperature. As in conventional instruments the heat generated by the sample flows through a thermal resistance into a water jacket and the resultant temperature difference, which is proportional to the rate of heat generation of the sample, is measured. But whereas normally the sample temperature is free to rise above the controlled jacket temperature, the new sample temperature control adjusts the water jacket temperature to maintain the sample near the set experiment temperature regardless of the temperature drop across the thermal resistance. This arrangement permits the use of a high thermal resistance to produce temperature differences in the range 0.1-10 deg C which are easily measured and recorded. The temperature control is a feedback system and the stability problems which may arise are discussed and a simple method of ensuring stability is presented. Details are given of a complete calorimeter, which produces a continuous record of the rate of heat generation of a 200 g sample of fish meal in the range 10-3-10-5 cal g-1 sec-1.

Some Remarks on the Measurement of Coefficient of Heat Transfer to Boiling Liquids

On the heat transfer to boiling liquids many investigations were carried out, but their results indicated no satisfactory coincidence. It arises from the existence of the mutal dependence between the generation of vapour bubbles and the flowing condition of liquids. The properties of heating surface, which influence directly on the generation of vapour bubbles have been hitherto discussed, but the heat loss from the side-wall of experimental apparatus has been out of consideration. This heat loss may influence on the flowing condition of liquids and the generating state of vapour bubbles. In this experiment we investigated the influence of heat loss from the side-wall of experimental apparatus on the coefficient of heat transfer. Experiments were carried out as follows : (1) heater ; upwards horizontal metal heating surface (dia. 10 cm) (2) liquids : distilled water (3) heat flux : 6560∼19690 kcal/m2h (4) jacket water temperature : 90∼100°C And we found that the heat loss from the side-wall of experimental apparatus influenced greatly on the coefficient of heat transfer to boiling liquids. Therefore, one must take care of this heat loss on the measurement of coefficient of heat transfer to boiling liquids.