Study concerning the thermal energy balance in an internal combustion engine

In this scientific report the steps for achieving the energy balance on a test engine Daewoo 1.6 liter in 4 cylinders, with 4 valves per cylinder, its power being77 kW, are presented. The engine was connected to a hydraulic brake during the tests. The energy balance was established, based on measurements applied on the stand test, focusing to determine the lost heat and to conceive a Sankey diagram, accordingly. Two sets of measurements were performed and based on them the heat losses were determined and two Sankey diagrams were depicted. The lost heat through the cooling fluid is determined by measuring the cooling water flow rate and its inlet and outlet temperature. The lost heat through the exhaust gases is determined by the difference between the enthalpy of the exhaust gases and the enthalpy of fresh air. The lost heat due to incomplete chemical combustion is determined by analyzing the composition of the exhaust gases. The measurements are centralized on a graphic user interface, supported by a NI Compact RIO platform.

Experimental Study of the Heat-Transfer Performance of an Extra-Long Gravity-Assisted Heat Pipe Aiming at Geothermal Heat Exploitation

The installation and operation of enhanced geothermal systems (EGS) involves many challenges. These challenges include the high cost and high risk associated with the investment capital, potential large working-fluid leakage, corrosion of equipment, and subsiding land. A super-long heat pipe can be used for geothermal exploitation to avoid these problems. In this paper, a high aspect-ratio heat pipe (30 m long, 17 mm in inner diameter) is installed vertically. Experiments are then carried out to study its heat-transfer performance and characteristics using several filling ratios of deionized water, different heating powers, and various cooling-water flowrates. The results show that the optimal filling-ratio is about 40% of the volume of the vaporizing section of the heat pipe. Compared with a conventional short heat pipe, the extra-long heat pipe experiences significant thermal vibration. The oscillation frequency depends on the heating power and working-fluid filling ratio. With increasing cooling-water flow rate, the heat-transfer rate of the heat pipe increases before it reaches a plateau. In addition, we investigate the heat-transfer performance of the heat pipe for an extreme working-fluid filling ratio; the results indicate that the lower part of the heat pipe is filled with vapor, which reduces the heat-transfer to the top part. Based on the experimental data, guidelines for designing a heat pipe that can be really used for the exploitation of earth-deep geothermal energy are analyzed.

Analisis Efektivitas Kondensor Di PLTU PT. Semen Tonasa Btg Unit I 2×25 MW

This research was conducted to determine the effect of fouling on the effectiveness of condensers in the Steam Power Plant (PLTU) PT. Semen Tonasa. The research method used is data collection in the central control room PLTU PT. Semen Tonasa. Steam temperature inlet condenser (Thin), temperature of condensate water (Thout), steam pressure inlet condenser (Ps), pressure of cooling water (Pcw), inlet temperature (Tcin) and outlet temperature of cooling water (Tcout), steam flow rate ( and cooling water flow rate () is the data needed in this research. Data were analyzed to get the value of effectiveness, number transfer of units (NTU), capacity ratio (C), log mean temperature different (LMTD) of the condenser. The results of the analysis showed that the decrease in condenser performance was influenced by the effect of fouling. Overhaul is done every 2 years. There was a decrease in NTU's value of 31.69% and an effective value of 22.29% in the period April 2016 to March 2018.

Investigation of thermal processes in hydrogen-oxygen steam generators of kilowatt power class

PURPOSE. Testing of a hydrogen-oxygen steam generator (HOSG) of the kilowatt power class for the study of heat and mass transfer processes. METHODS. At the first stage, the technological system of diagnostics and control was considered, with the help of which preliminary tests were carried out. According to the results of which the structural elements of the HOSG were modernized. Further, at the second stage, an automated process control system was created, which ensured the conduct of multi-mode tests of the HOSG. RESULTS. The design of the HOSG showed its efficiency. The changes in the cooling water flow rate, pressure and temperature in the evaporation chamber during multi-mode tests are presented, as well as the generalized results of experimental studies, which show the dependence of the steam temperature on the mass fraction of water at different coefficients of the excess oxidizer.CONCLUSION. During the preliminary tests, the development of upgraded components of the HOSG was carried out, ensuring an increase in the efficiency of its operation. The created automated control system made it possible to successfully conduct subsequent multi-mode tests with two different types of cameras. The indicators of unreacted hydrogen are comparable to those already achieved in existing devices. The characteristic transition times from mode to mode show compliance with the requirements for creating autonomous power plants based on renewable energy sources.

OPTIMATION OF FIRE EXTINGUISHMENT SYSTEMS IN X STATION CENTER OF CRUDE OIL AND GAS STORAGE

This paper discusses some research results that were carried out to optimize the fire extinguishment system of X Station in South Sumatera. To optimize the fire extinguishing system at station X, a system modification has been done, which included: changes in the number of stockpile tank units, changes in capacity and dimensions of oil tanks, and changes in fire wall construction. With the change in capacity and dimensions, especially the storage tank unit, it is necessary to recalculate whether the water demand in the fire protection system is still sufficient according to the existing system condition. From this research, it can be concluded that the maximum flow rate of foam under the existing condition is 1631.6 gpm while the optimum ondition is 65% smaller than the existing system condition at 570.54 gpm. The cooling water flow rate of 615.09 gpm at optimum ondition is lower than the existing system conditions of 1409.33 gpm. The required water to the fire extinguishment system is 250 gpm; this value is smaller than the existing system capacity of 2074 gpm. By using performance curves of Grundfos Data Booklet, for the capacity of pump 1250 gpm, the total head pump and pump efficiency are obtained 103.48 m and 77.5 %, respectively. Keywords: optimation; tank; water; foam; pump

EMbaffle® Heat Transfer Technology Step-Up in CO2 Reduction

EMbaffle® is a proprietary shell and tube heat exchanger technology, designed to improve performance by pressure drops control, with suppressed tube vibrations. Developed to minimize fouling accumulation in crude oil units, the technology has proved to be effective in Gas treatment and Petrochemical, supporting the increase in gas–gas and cooling water flow rate per-unit demand, and in Renewable CSP, where Molten Salt units get a primary role in thermal storage and power efficiency. Diamond shape and baffle-grids number are the instruments for the design engineer to exploit exchanger efficiency against pressure drops, aimed to the desired performance with the optimized power consumption. Further to introduce the base of the technology, this work will also address the design of higher compact units by combining the grids performance with the improved exchanger tube surface. Experimental data to support the grid life under critical working conditions and actual performances with fluids density and viscosity are reported.

Design improvement and experimental study on shell and tube condenser for bio-oil recovery from fast pyrolysis of wheat straw biomass

In this study, the design improvement was done in a shell and tube condenser for improved heat transfer and condensation of bio-oil vapour. The developed condenser has split shell and segmental baffles, which divide the shell in various zones and condensate collection points. The fast pyrolysis of wheat straw was done and the bio-oil vapour condensate collected from various outlets located at bottom of condenser shell. From experimental results it was found that production of bio-oil increased from 10.2 to 20.8% with increase in cooling water flow rate from 1000 to 2500 L/h; but, further increasing it beyond 2500 L/h provide marginal effects on production of bio-oil. The production of bio-oil increased from 15.2 to 20.7% as sweep gas flow rate was increased from 20 to 40 L/min at 2500 L/h of cooling water flow rate. But, further increase in sweep gas flow rate beyond 40 L/min resulted in to decrease in production of bio-oil. The novelty of this work is development of improved condenser with segmental baffles, which help in fractional condensation of bio-oil vapour, split shell for cleaning of outer surface of the cooling water tubes and compact design of condenser for optimal condensation of bio-oil.

Design and verification of ultra-high temperature lithium heat pipe based experimental facility

Lithium heat pipe has broad applications in heat pipe cooled reactors and hypersonic vehicles due to its ultra-high working temperature which is around 1700 K. In this paper, a lithium heat pipe based experimental facility has been designed to test the heat transfer performance of the lithium heat pipe. A simplified mathematical model of heat pipe has been implemented into a CFD approach, which is used to verify the design of lithium heat pipe and its experimental facility. Results showed that the CFD approach is in good agreements with some well-known existing models and experimental data, and deviation between the results is within 5% range. The adjustment range of mixed gas thermal resistance and cooling water flow rate was obtained by analyzing the effects of different cooling conditions on the performance of the experimental facility. It is necessary to ensure the cooling water flow rate is above 0.11l/h to prevent water boiling when the heating power is10kW around, and the optimal proportion of helium is 70% -90%.The operation characteristics of the lithium heat pipe under unsteady state with varying heating power were simulated numerically. The results show that the proportion of helium must be less than 60% for normal operation of the lithium heat pipe. This work provides a reference and numerical verification for the design of lithium heat pipe based experimental facility, which can be used to reveal the heat transfer mechanisms of the lithium heat pipe during the experiment.

Experimental Study on the Desalination System Using Humidification-Dehumidification Technology

In this paper, an experimental work studies the principal operating parameters of a proposed desalination process using air humidification-dehumidification method. The major objective of this work is to determine the humid air behavior through the desalination system. Different operating conditions including the effect of the water temperature at the entry to the humidifier, the ratio of the mass of water to the air, the air/water flow rate, and cooling water at entry the dehumidifier on the desalination performance were studied. The results show that the freshwater increases with increasing the water temperature at the inlet of the humidifier, the ratio of the mass of water to air, and cooling water flow rate in the dehumidifier. Cooling water outlet temperature at the condenser increases with increasing the water temperature at humidifier inlet. Also, it decreases as increasing cooling water flow rate while the ratio of the mass of water to air achieves the highest productivity and gained output ratio (GOR). The achieved mass ratio (MR) is 4.5 and the mass flow rate of air is 0.8 kg/min.