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The Ramage method1 for the spectrochemical analysis of solutions has been developed by other workers2. In this method, filter paper is impregnated with the solution and is introduced into the flame or arc in the form of a roll or strip. Mechanical devices have been designed to ensure the steady combustion of the sample2.

The purpose of this paper is to review, necessarily rather superficially, the broad question of emissions from diesel engines and their relation to combustion as seen from an engineer's point of view. From the previous paper it will be realized that smoke is the emission currently under strongest scrutiny. Nevertheless, as gasoline engine emissions are brought under more rigorous control there also will be pressure to control unburnts, oxides of nitrogen, and other emissions from diesel engines.

The paper is set in a background of boiler commissioning for customers in power generating, industrial, marine, petro-chemical and oil-refining companies in Britain and overseas. Some of the problems encountered during the commissioning of a diversity of units employing solid fuel, oil fuels, naphtha, gas fuel firing, either singly or in combination, are discussed, and actual case histories detailed. The paper embraces difficulties experienced with the ignition of fuels, the control of flame shape, air distribution to burners, layout of fuel supply lines, safety circuits, and the necessity for close collaboration between the customer and the designer during the tender and contract stages, in order to avoid loss of availability, resulting from delays in commissioning or subsequent damage to equipment.

This paper investigates the reasons for the changing face of the gas industry and discusses the wide range of installations utilizing gaseous fuel for space and comfort heating. The gaseous fuels available in the U.K. are examined and the fundamental principles of combustion and control and the safeguards incorporated in appliances are outlined. The problems of conversion from town gas to natural gas are also dealt with. The main part of the paper is a review of types of gas installation used for space heating and cooling. Domestic, commercial and industrial installations and district heating are dealt with separately and the engineering and design details are given, supported by extensive references. Particular reference is made to installations peculiar to gas. The paper suggests a promising future for gas, and an attempt is made to indicate future trends in utilization and fuel costs.

The paper is introduced with a discussion on how a knowledge of total pressures in exhaust systems would help in the development of internal combustion engines. The concept of a total pressure in a steady flow is straightforward and well known but it is shown that under unsteady flow conditions the concept needs further qualification. A full discussion on the matter is given in the paper. A brief review of previous work on similar types of probes is presented before the ‘Fecheimer’ type of probe is described. In order to test the probes a special ‘simple wave’ technique was used. A discussion of the technique together with the theory on which it is based is included. The tests on the Fecheimer type of probe are described and results presented. The second type of probe, which was an impact-tube type, is also described. The tests on the second type of probe revealed interesting results which were explained by a theoretical calculation. Details of the test results and the theoretical analysis which explain the results are discussed. It is shown that the theory could explain some of the results obtained with the Fecheimer type of probe. Finally, conclusions are given on the concept of a total pressure and the results of the tests carried out on the probes are discussed.

Paper spheres with initial diameters (d0) ranging from 0.8 cm to 4.5 cm have been burned in air, at variable speeds ranging from zero to 160 cm/sec, and oxygen concentrations from 21% to 70%. The burning times (tb) were found to obey a fairly close approximation of the standard “square-law” relation even though 80% of the mass loss was by pyrolysis. The burning constant (Kb) in the equation obtained: tb=Kb·d01.85; was a function of velocity, decreasing up to Re=2800 (based on the combustion tube), and then increasing again beyond that. The burning times also became almost linear with diameter indicating a transition from diffusional to kinetic dominance at Re, based on the sphere, of 2000. The variation of Kb with oxygen concentration was substantially as predicted; and adequate agreement was obtained between the experimental and calculated values of the burning constant KD of the char alone, and also of the combustion temperature. Simultaneous weight and diameter measurements were also made as these varied with time. From these, densities were calculated showing that the char residue that remained after termination of pyrolysis, burned out at constant density. The conclusions were that the pyrolysis and the char combustion were substantially independent (except for competition for oxygen), with both proceeding simultaneously for 80% of the total weight loss. Even so, char burn-out, of 10% of the total weight, took 60% of the burning time in air. The relevance of these data to incinerator behavior is also discussed.

Previous work on non-steady flow in exhaust systems has shown that the method of characteristics can be used to predict the flow conditions to a high degree of accuracy. In these calculations the pressure at the inlet port or valve was considered to be constant. Recent work on the effect of pulsating flow on centrifugal compressors has shown the importance of considering non-steady flows in the inlet systems of supercharged engines. Predictions of the non-steady flow in inlet systems, usually based on acoustic theory, have only been accurate in particular cases. In this paper the method of characteristics has been applied to the study of non-steady flows both in the inlet and exhaust systems of internal combustion engines. Comparisons are made between the calculated and experimental results obtained on a multi-cylinder pulse generator. Tests on both single- and two-cylinder units were carried out and measurements of the inlet pipe pressure, exhaust pipe pressure, cylinder pressures and temperatures, and inlet and exhaust mass flows were made. Comparisons between the theoretical predictions and the test results were extremely good; in all the cases the pressures were in close agreement. The inlet predicted mass flows were all within +9 and −4 per cent of the measured flows, the standard deviation being 3·1 per cent. The exhaust mass flows were all within +8 and −12 per cent of the measured mass flows, the standard deviation being 4·3 per cent. It was considered that the method gives reliable predictions of the flow processes in internal combustion engines.

Measurement of both the mean and instantaneous values of gas velocity in internal combustion (i.c.) engines presents problems of considerable difficulty and the application of electronic methods of measurement has made important contributions in this field. The problems encountered in metering pulsating flows are briefly discussed with special reference to the advantages of two metering devices which employ electronic circuits. Whilst pressure transducers enable the variation in instantaneous gas velocities to be inferred in certain circumstances there are many other cases where a direct indication of velocity variation is desirable. The hot wire anemometer (h.w.a.) has been highly developed for aeronautical engineering applications but special problems arise in the reciprocating engine where velocity variations can be large. This paper describes a constant temperature h.w.a. using a d.c. circuit which has proved stable and relatively easy to operate. If velocity measurements in the engine cylinder are required the problem becomes a three-dimensional one, and the response of the h.w.a. to variation in flow direction is discussed. Consideration is given to materials suitable for probe wires.

This paper describes the development of a meter, employing the radial disc principle, for measurements of the local heat flux to the water/steam tube surfaces of boiler furnaces. The design and material requirements are stated for the meter to operate successfully in the arduous conditions of a combustion chamber. The development of the meter is followed from the initial prototype to the proving of the final design.

This paper concentrates on the combustion experience gained by the application of the Rolls-Royce Avon aero gas turbine to industrial usage and each of the following subjects is considered in detail. A brief summary of the design philosophy which has dictated the configuration of the basic aero combustion equipment. The particular implications of industrial operation as this affects the combustion system. This includes the effect of different fuels and operation for long periods in a ground level environment. The operational problems experienced to date with the basic aero equipment and the design and development work undertaken to overcome them. These problems comprise frettage, flare distortion, smoke output, starting, corrosion and combustion stability. The design and development of an improved system, now under way, which will be capable of satisfactory operation with a wide range of liquid or gaseous fuels without component change. The use of steam injection into the combustion system as a means of improving overall cycle efficiency. Consideration of the range of industrial fuels available, from diluted gases to distillate and residual oils, and their suitability for gas turbine usage. Future trends in combustion technology.

The several positions in engine fluid systems in which cooling equipment is commonly used are examined and the fluid pressures and temperatures to which the heat exchangers are subjected outlined. General considerations affecting the designs from the points of view of performance (heat transfer and power loss) and environment (chemical and mechanical) are examined and amongst other points it is shown that the best ratio of cooling surfaces in a secondary surface heat exchanger is If ρ = 1 this reduces to r = √ R which is very different from the usual recommendation that r and R should be equal. The second part of the paper is descriptive, and deals with the mechanical design of heat exchangers used for cooling engines in various applications: marine engines; stationary engines; locomotive and railcar engines; agricultural machinery; road vehicles; and aircraft.

The paper commences with a definition of the requirements of cylinder pressure measurements for (1) general engine development work, (2) frequency spectrum analysis in engine noise investigation, and (3) thermodynamics and combustion analysis. Methods for the determination of the frequency response of cylinder pressure transducers are then treated both theoretically and experimentally. For the continuous recording type of transducer a shock chamber technique is used. For the balanced pressure type of pick-up a comparison with a continuous recording type, of known frequency response, is made. These techniques do not completely simulate engine conditions and comparisons of the two types of pressure transducers were made dynamically under engine conditions. The results showed that all the continuous recording types of pressure transducer so far tested were sensitive to transient heat transfer owing to combustion. A rig was therefore developed to simulate such conditions outside the engine. Detailed descriptions are given of examples of both types of pressure transducer as developed at C.A.V. The method of recording timing marks is presented in some detail and the advantage of the ‘closed circuit’ magnetic type of degree pick-up is described.

The amount of NO (nitric oxide) developed during the combustion and expansion phases of the spark-ignition engine cycle has been calculated using several different kinetic formulations, for a range of fuel-air ratios at each of two compression ratios. Comparing the results shows the effects of including or omitting certain reactions and of applying the quasi-stationary assumption to the concentrations of N and N2O.