Category: Steam Engines

Typical performance curves of a reciprocating steam engine under test conditions are shown in Fig. 5.21. Most of the curves are self-explanatory and should be carefully scrutinised for analysis of the variables involved. One salient fact is that the speed curve as shown is practically horizontal with a slight drop as the load is increased, this…

Procedure: For preparing a heat balance sheet for a steam engine cylinder, the engine should be tested over a period of time under conditions of constant load and steam supply. An indicator diagram should be taken and the steam pressure noted at regular intervals of time, an account should also he kept of the steam supply…

Saturation Curve: The saturation curve is the curve showing the volume the steam in the cylinder would occupy, during the expansion stroke if the steam is perfectly dry and saturated at all the points. It is plotted on p–V diagram and the wetness of stream can be seen on it at a glance. Figure 5.18 shows a calibrated indicator. The total…

The steam supply to a steam engine is at 15 bar dry and saturated. The condenser pressure is 0.4 bar. Calculate the Rankine efficiency of the cycle. Neglect pump work. Solution Given: p1 = 15 bar, p2 = 0.4 bar, x1 = 1.0 From steam tables at 15 bar, h1 = hg = 2789.9 kJ/kg, s1 = sg = 6.4406 kJ/kg.K At 0.4 bar, hf 2 = 317.7 kJ/kg, hfg2 = 2319.2…

The automatic variation of steam supply with the variation of load is called governing and the device used for this purpose is known as a governor. There are two methods commonly used for steam engine governing. The indicated power vs steam consumption per minute for throttle and cut-off governing are shown in Fig. 5.15. It is obvious from…

1 Indicated Power The power developed by the steam engine based on the indicator diagram is the indicated power. Work done by the steam engine per cycle is given by, w = Force × distance travelled by the piston Work done per second is the indicated power where  on cover end side.  on crank end side. d = diameter…

The mean effective pressure is a quantity related to the operation of an internal combustion engine. It is a valuable measure of an engine’s capacity to do work that is independent of engine displacement. 1 Without Clearance The theoretical p-v diagram for a single acting steam engine without clearance is shown in Fig. 5.9(a). It can be obtained…

Indicator diagram is simply a graph between pressure of steam in a cylinder against the steam volume. The following assumptions are made in drawing the theoretical indicator diagram: The theoretical and actual indicator diagrams are shown in Fig. 5.8. The actual indicator diagram is found to be different from the theoretical diagram due to following reason:…

The indicator diagram is a representation of the variations of pressure and volume of steam inside the cylinder on p-V diagram for one complete cycle of operation. The theoretical p-v diagram for a single acting steam engine is shown in Fig. 5.7 without and with clearance. The sequence of operations is as follows: Process 1-2: The steam is supplied to…

In modified Rankine cycle to reduce friction the stroke length is reduced. Figure 5.6(a) and 5.6(b) show the modified Rankine cycle on p-v and T-s diagrams respectively, by neglecting pump work. It may be observed that p-v diagram is very narrow at the toe. i.e., point 3′. The work obtainable near to 3′ is very small which is too inadequate to overcome friction…